Exhibit 4.15
                          REGISTRATION RIGHTS AGREEMENT

          REGISTRATION RIGHTS AGREEMENT, dated as of August 17, 1999, by and
among Concentra Managed Care, Inc., a Delaware corporation (the "COMPANY"), the
several persons named in Schedule I hereto (collectively, the "SCHEDULE I
PURCHASERS") and the person named in Schedule II hereto (the "CHASE PURCHASER"),
each of whom has agreed to purchase the Company's 14% Senior Discount Debentures
due 2010 (the "DEBENTURES") pursuant to the Purchase Agreement (as defined
below). The Schedule I Purchasers and the Chase Purchaser are herein sometimes
referred to collectively as the "PURCHASERS."

          WHEREAS, this Agreement is made pursuant to the Purchase Agreement as
of dated August 17, 1999 (the "PURCHASE AGREEMENT") by and among the Company and
the Purchasers and in order to induce the Purchasers to purchase the Debentures,
the Company has agreed to provide the registration rights set forth in this
Agreement.

          NOW, THEREFORE, in consideration of the premises and of the mutual
covenants and agreements herein contained, the parties hereto hereby agree as
follows:

          1. CERTAIN DEFINITIONS. Capitalized terms used herein and not
otherwise defined shall have the meaning assigned to them in the Indenture,
dated as of August 17, 1999, between the Company and United States Trust Company
of New York, as Trustee, relating to the Debentures (the "INDENTURE"). In
addition to the terms defined elsewhere herein, the following terms shall have
the following respective meanings when used herein with initial capital letters:

          "BOARD" means the Board of Directors of the Company.

          "COMMISSION" shall mean the Securities and Exchange Commission, or any
     other federal agency at the time administering the Securities Act.

          "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934 or any
     similar federal statute, and the rules and regulations of the Commission
     thereunder, all as the same shall be in effect at the time.

          "REGISTRATION EXPENSES" shall mean the expenses so described in
     Section 8 hereof.

          "SECURITIES ACT" shall mean the Securities Act of 1933 or any similar
     federal statute, and the rules and regulations of the Commission
     thereunder, all as the same shall be in effect at the time.

          "SELLING EXPENSES" shall mean the expenses so described in Section 8
     hereof.






          2. DEMAND REGISTRATION.

          (a) At any time after the Issue Date, the holders of a majority in
aggregate principal amount at maturity of the outstanding Debentures may request
the Company to register under the Securities Act all or any portion of the
Debentures held by such requesting holder or holders for sale in the manner
specified in such notice. At any time after the third anniversary of the Issue
Date, the Chase Purchaser may make one request to the Company to register under
the Securities Act all of the Debentures held by such requesting holder for sale
in the manner specified in such notice.

          (b) Promptly following receipt of any notice under this Section 2, the
Company shall immediately notify any holders of Debentures from whom notice has
not been received and shall use its best efforts to register as soon as possible
under the Securities Act, for public sale in accordance with the method of
disposition specified in such notice from the original requesting holders, the
principal amount at maturity of the Debentures specified in such notice (and in
any notices received from other holders of Debentures within 20 days after their
receipt of such notice from the Company). The original requesting holders may
choose the managing underwriter (which shall be a nationally recognized
investment banking firm), subject to the consent of the Company (which shall not
be unreasonably withheld). Notwithstanding anything to the contrary contained
herein, the obligation of the Company under this Section 2 shall be deemed
satisfied only when a registration statement covering all of the principal
amount at maturity of the Debentures specified in notices received as aforesaid,
for sale in accordance with the method of disposition specified by the
requesting holder, shall have become effective.

          (c) The Company shall not be obligated to file a registration
statement relating to any registration request under this Section 2:

               (i) if with respect thereto the managing underwriter, the
          Commission, the Securities Act or the rules and regulations
          thereunder, or the form on which the registration statement is to be
          filed, would require the conduct of an audit other than the regular
          audit conducted by the Company at the end of its fiscal year, in which
          case the filing may be delayed until the completion of such audit (and
          the Company shall, upon request of the parties demanding registration
          pursuant to this Section 2, use its reasonable efforts to cause such
          audit to be completed expeditiously and without unreasonable delay);

               (ii) if the Company is in possession of material non-public
          information and the Board determines in good faith that disclosure of
          such information would not be in the best interests of the Company and
          its stockholders, in which case the filing of the registration
          statement may be delayed until the earlier of (i) the second business
          day after such conditions shall have ceased to exist and (ii) the

                                       2




          90th day after receipt by the Company of the written request from the
          holders specified in paragraph (a) above; or

               (iii) within a period of 180 days (or such lesser period as the
          managing underwriters in an underwritten offering may permit) after
          the effective date of any other registration statement relating to any
          securities of the Company.

          3. REGISTRATION PROCEDURES. If and whenever the Company is required by
the provisions of Section 2 hereof to use its best efforts to effect the
registration of any of the Debentures under the Securities Act, the Company
will, as expeditiously as possible:

          (a) in accordance with the Securities Act and all applicable rules and
     regulations, prepare (and afford counsel for the selling holders reasonable
     opportunity to review and comment thereon) and file with the Commission a
     registration statement with respect to such securities and use its best
     efforts to cause such registration statement to become and remain effective
     for the period of the distribution contemplated thereby (determined as
     hereinafter provided);

          (b) prepare (and afford counsel for the selling holders reasonable
     opportunity to review and comment thereon) and file with the Commission
     such amendments and supplements to such registration statement and the
     prospectus used in connection therewith and any documents incorporated by
     reference therein and file such other documents as may be necessary to keep
     such registration statement effective for the period specified in paragraph
     (a) above and to comply with the provisions of the Securities Act with
     respect to the disposition of all Debentures covered by such registration
     statement in accordance with the sellers' intended method of disposition
     set forth in such registration statement for such period;

          (c) furnish to each seller and to each underwriter such number of
     copies of the registration statement and the prospectus included therein
     (including each preliminary prospectus), and all amendments, supplements,
     and exhibits thereto, and such other documents as such persons may
     reasonably request in order to facilitate the public sale or other
     disposition of the Debentures covered by such registration statement (and
     the Company hereby consents to the use of any such prospectus, together
     with such supplements and amendments, by the sellers and underwriters, if
     any, in connection with the offer and sale covered thereby);

          (d) use its best efforts to register or qualify the Debentures covered
     by such registration statement under the securities or blue sky laws of
     such jurisdictions as the sellers of Debentures or, in the case of an
     underwritten offering, the managing underwriter, shall reasonably request
     (provided that the Company will not be required to (i) qualify generally to
     do business in any jurisdiction where it would not otherwise be

                                       3




     required to qualify but for this paragraph (d), (ii) subject itself to
     taxation in any such jurisdiction or (iii) consent to general service of
     process in any jurisdiction);

          (e) immediately notify each seller under such registration statement
     and each underwriter, (i) when such registration statement or any
     post-effective amendment or supplement thereto becomes effective or a
     supplement to any prospectus forming a part of such registration statement
     has been filed; (ii) of the issuance by the Commission or any state
     securities authority of any stop order, injunction or other order or
     requirement suspending the effectiveness of such registration statement
     (and the Company shall use best efforts to prevent the initiation of
     proceedings for, prevent the entry of and/or remove such order or
     requirement); (iii) of the happening of any event as a result of which such
     registration statement, as then in effect, the prospectus contained therein
     or any document incorporated by reference therein includes an untrue
     statement of a material fact or omits to state any material fact required
     to be stated therein or necessary to make the statements therein not
     misleading in the light of the circumstances then existing; or (iv) of any
     request by the Commission for the amending or supplementing of such
     registration statement or prospectus or for additional information;

          (f) use its best efforts to furnish, at the request of any seller, on
     the date that Debentures are delivered to the underwriters for sale
     pursuant to such registration, if such securities are being sold through
     underwriters, or on the date that the registration statement becomes
     effective, if such securities are not being sold through underwriters: (i)
     an opinion dated such date of counsel representing the Company for the
     purposes of such registration, addressed to the underwriters, if any, and
     to such seller, stating that such registration statement has become
     effective under the Securities Act and that (A) to the best knowledge of
     such counsel, no stop order suspending the effectiveness thereof has been
     issued and no proceedings for that purpose have been instituted or are
     pending or contemplated under the Securities Act, (B) the registration
     statement, the related prospectus, and each amendment or supplement
     thereof, comply as to form in all material respects with the requirements
     of the Securities Act and the applicable rules and regulations of the
     Commission thereunder (except that such counsel need express no opinion as
     to financial statements, the notes thereto, and the financial schedules and
     other financial and statistical data contained therein) and (C) to such
     other effects as may reasonably be requested by counsel for the
     underwriters or by such seller or its counsel, and (ii) a letter dated such
     date from the independent public accountants retained by the Company,
     addressed to the underwriters, if any, and to such sellers stating that
     they are independent public accountants within the meaning of the
     Securities Act and that, in the opinion of such accountants, the financial
     statements of the Company included in the registration statement or the
     prospectus, or any amendment or supplement thereof, comply as to form in
     all material respects with the applicable accounting requirements of the
     Securities Act, and such letter shall additionally cover such other
     financial matters (including information as to the period ending no more
     than five business days prior to

                                       4




     the date of such letter) with respect to the registration in respect of
     which such letter is being given as such underwriters or sellers may
     reasonably request;

          (g) take such actions as may be necessary or appropriate to obtain a
     CUSIP number (if none exists) for the Debentures and make all filings and
     secure all approvals required pursuant to the regulations of the National
     Association of Securities Dealers, Inc. in connection with such
     registration;

          (h) use its best efforts to comply with all applicable rules and
     regulations of the Commission, and make available to any holder of
     Debentures as soon as reasonably practicable (but not more than 15 months)
     after the effective date of the registration statement, an earnings
     statement which shall satisfy the provisions of Section 11(a) of the
     Securities Act and the rules and regulations promulgated thereunder; and

          (i) make available for inspection by each seller, any underwriter
     participating in any distribution pursuant to such registration statement,
     and any attorney, accountant or other agent retained by such seller or
     underwriter, all financial and other records, pertinent corporate documents
     and properties of the Company, and cause the Company's officers, directors
     and employees to supply all information reasonably requested by any such
     seller, underwriter, attorney, accountant or agent in connection with such
     registration statement and permit such seller, attorney, accountant or
     agent to participate in the preparation of such registration statement.

For purposes of paragraphs (a) and (b) above and of Section 2(c) hereof, the
period of distribution of Debentures in a firm commitment underwritten public
offering shall be deemed to extend until each underwriter has completed the
distribution of all Debentures purchased by it, and the period of distribution
of Debentures in any other registration shall be deemed to extend until the
earlier of the sale of all Debentures covered thereby or six months after the
effective date thereof.

          In connection with each registration hereunder, the selling holders of
Debentures will furnish to the Company in writing such information with respect
to themselves and the proposed distribution by them as shall be reasonably
necessary in order to assure compliance with federal and applicable state
securities laws.

          In connection with each registration pursuant to Section 2 hereof
covering an underwritten public offering, the Company agrees to enter into a
written agreement with the managing underwriter selected in the manner herein
provided in such form and containing such provisions as are customary in the
securities business for such an arrangement between major underwriters and
companies of the Company's size and investment stature; PROVIDED, HOWEVER, that
such agreement shall not contain any such provision applicable to the Company
which is inconsistent with the provisions hereof and PROVIDED, FURTHER, HOWEVER,
that the time and place of

                                       5




the closing under said agreement shall be as mutually agreed upon among the
Company, such managing underwriter and the selling holders of Debentures.

          4. EXPENSES. All expenses incurred by the Company in complying with
Section 2 hereof, including, without limitation, all registration, listing and
filing fees, printing expenses, fees and disbursements of counsel and
independent public accountants for the Company (including with respect to any
special audit or "cold comfort" letters), fees of the National Association of
Securities Dealers, Inc., transfer taxes and fees of transfer agents and
registrars, as well as reasonable fees and out-of pocket expenses of not more
than one counsel for all the Purchasers but excluding any Selling Expenses, are
herein called "REGISTRATION EXPENSES." All underwriting discounts and selling
commissions applicable to the sale of Debentures are herein called "SELLING
EXPENSES."

          The Company will pay all Registration Expenses in connection with each
registration statement filed pursuant to Section 2 hereof. All Selling Expenses
in connection with any registration statement filed pursuant to Section 2 hereof
shall be borne by the participating sellers in proportion to the principal
amount at maturity of Debentures sold by each, or by such persons as they may
agree.

          5. INDEMNIFICATION. In the event of a registration of any of the
Debentures under the Securities Act pursuant to Section 2 hereof, the Company
will indemnify and hold harmless, to the fullest extent permitted by law, each
seller of such Debentures thereunder, each underwriter of Debentures thereunder,
each of their respective affiliates, each of their and their affiliates'
respective directors, officers, fiduciaries, trustees, agents, employees,
stockholders, general and limited partners and members, and each other person,
if any, who controls such seller or underwriter within the meaning of the
Securities Act, against any losses, claims, damages or liabilities, joint or
several, actions or proceedings (whether commenced or threatened) in respect
thereof (all of the foregoing, collectively, "CLAIMS") and expenses (including
fees and expenses of counsel, and amounts paid in any settlement effected with
the Company's consent, which consent shall not be unreasonably withheld or
delayed) to which such indemnified party may become subject under the Securities
Act or otherwise, insofar as such Claims or expenses arise out of or are based
upon any untrue statement or alleged untrue statement of any material fact
contained in any registration statement under which such Debentures were
registered under the Securities Act pursuant to Section 2, any preliminary
prospectus, summary or final prospectus contained therein, or any amendment or
supplement of any thereof, or any documents incorporated by reference therein,
or arise out of or are based upon the omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading, and will reimburse each such indemnified
party for any legal or other expenses incurred by them in connection with
investigating or defending any such Claim; PROVIDED, HOWEVER, that the Company
will not be liable to any such indemnified party if and to the extent that any
such Claim or expense arises out of or is based upon an untrue statement or
alleged untrue statement or omission or alleged omission so made in conformity

                                       6




with information pertaining to such indemnified party furnished by such
indemnified party in writing specifically for use in such registration statement
or prospectus.

          In the event of a registration of any of the Debentures under the
Securities Act pursuant to Section 2 hereof, each seller of such Debentures
thereunder, severally and not jointly, will indemnify and hold harmless, to the
fullest extent permitted by law, the Company and each person, if any, who
controls the Company within the meaning of the Securities Act, each officer of
the Company who signs the registration statement, each director of the Company,
each underwriter and each person who controls any underwriter within the meaning
of the Securities Act, each other holder selling Debentures under such
registration statement and each affiliate, officer, director, fiduciary,
trustee, agent, employee, stockholder, general or limited partner or member of
such selling holder against all Claims and expenses (including fees and expenses
of counsel, and amounts paid in any settlement effected with the indemnifying
party's consent, which consent shall not be unreasonably withheld or delayed) to
which the Company or such officer or director or underwriter or controlling
person may become subject under the Securities Act or otherwise, insofar as such
Claims or expenses arise out of or are based upon any untrue statement or
alleged untrue statement of any material fact contained in the registration
statement under which such Debentures were registered under the Securities Act
pursuant to Section 2, any preliminary prospectus, summary or final prospectus
contained therein, or any amendment or supplement of any thereof, or any
documents incorporated by reference therein, or arise out of or are based upon
the omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, and
will reimburse the Company and each such indemnified party for any legal or
other expenses incurred by them in connection with investigating or defending
any such Claim; PROVIDED, HOWEVER, that such seller will be liable hereunder to
any such indemnified party if and only to the extent that any such Claim or
expense arises out of or is based upon an untrue statement or alleged untrue
statement or omission or alleged omission made in reliance upon and in
conformity with information pertaining to such seller, as such, furnished in
writing to the Company by such seller specifically for use in such registration
statement or prospectus; PROVIDED, FURTHER, HOWEVER, that the liability of each
seller hereunder shall be limited to the proceeds (net of underwriting discounts
and commissions) received by such seller from the sale of Debentures covered by
such registration statement.

          Promptly after receipt by an indemnified party hereunder of notice of
the commencement of any action, such indemnified party shall, if a claim in
respect thereof is to be made against the indemnifying party hereunder, notify
the indemnifying party in writing thereof, but the omission so to notify the
indemnifying party shall not relieve it from any liability which it may have to
such indemnified party under this Section 5 except to the extent such
indemnifying party is materially prejudiced thereby, and in any event will not
relieve such indemnifying party from any liability which it may have to any
indemnified party other than under this Section 5. In case any such action shall
be brought against any indemnified party and it shall notify the indemnifying
party of the commencement thereof, the indemnifying party shall be entitled to
participate in and, to the extent it shall wish, to assume and undertake the
defense thereof with

                                       7




counsel satisfactory to such indemnified party, and, after notice from the
indemnifying party to such indemnified party of its election so to assume and
undertake the defense thereof, the indemnifying party shall not be liable to
such indemnified party under this Section 5 for any legal expenses subsequently
incurred by such indemnified party in connection with the defense thereof other
than reasonable costs of investigation and of liaison with counsel so selected;
PROVIDED, HOWEVER, that, if the defendants in any such action include both the
indemnified party and the indemnifying party and the indemnified party shall
have reasonably concluded that there may be reasonable defenses available to it
which are different from or additional to those available to the indemnifying
party, or if the interests of the indemnified party reasonably may be deemed to
conflict with the interests of the indemnifying party, or if the indemnifying
party shall not diligently continue such defense in good faith, the indemnified
party shall have the right to select a separate counsel and to assume such legal
defenses and otherwise to participate in the defense of such action, with the
expenses and fees of such separate counsel and other expenses related to such
participation to be reimbursed by the indemnifying party as incurred.

          Notwithstanding the foregoing, any indemnified party shall have the
right to retain its own counsel in any such action, but except as set forth
above the fees and disbursements of such counsel shall be at the expense of such
indemnified party unless (i) the indemnifying party shall have failed to retain
counsel for the indemnified person as aforesaid or (ii) the indemnifying party
and such indemnified party shall have mutually agreed to the retention of such
counsel. It is understood that the indemnifying party shall not, in connection
with any action or related actions in the same jurisdiction, be liable for the
fees and disbursements of more than one firm (together with local counsel) to
act as counsel for the indemnified party. The indemnifying party shall not be
liable for any settlement of any proceeding effected without its written consent
(which shall not be unreasonably withheld or delayed), but if settled with such
consent or if there be a final judgment for the plaintiff, the indemnifying
party agrees to indemnify the indemnified party from and against any loss or
liability by reason of such settlement or judgment. No indemnifying party shall,
without the written consent of the indemnified party (which shall not be
unreasonably withheld or delayed), effect the settlement or compromise of, or
consent to the entry of any judgment with respect to, any pending or threatened
action in respect of which indemnification may be sought hereunder (whether or
not the indemnified party is an actual or potential party to such action) unless
such settlement, compromise or judgment (i) includes an unconditional release of
such indemnified party from all liability arising out of such action and (ii)
does not include a statement as to or an admission of fault, culpability or a
failure to act by or on behalf of such indemnified party.

          If for any reason the indemnification provided for in the first two
paragraphs of this Section 5 is unavailable or insufficient to hold harmless an
indemnified party under such paragraphs in respect of any Claims or expenses in
respect thereof referred to therein, then each indemnifying party shall in lieu
of indemnifying such indemnified party contribute to the amount paid or payable
by such indemnified party as a result of such Claims or expenses in such
proportion as appropriate to reflect the relative fault of the Company, on the
one hand, and the underwriters and the sellers of such Debentures, on the other,
in connection with the statements

                                       8




or omissions which resulted in such Claims or expenses as well as any other
relevant equitable considerations, including the failure to give any notice
under the third paragraph of this Section 5. The relative fault shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact relates to information supplied by the
indemnifying party, on the one hand, or the indemnified party, on the other, and
to the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission. The Company and
each of you agree that it would not be just and equitable if contributions
pursuant to this paragraph were determined by PRO RATA allocation (even if all
of the sellers of such Debentures were treated as one entity for such purpose)
or by any other method of allocation which did not take account of the equitable
considerations referred to above in this paragraph. The amount paid or payable
by an indemnified party as a result of the Claims and expenses in respect
thereof, referred to above in this paragraph, shall be deemed to include any
legal or other expenses reasonably incurred by such indemnified party in
connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this paragraph, no seller of such Debentures
or related indemnified party shall be required to contribute any amount in
excess of the amount of proceeds (net of underwriting discounts and commissions)
received by such seller from the sale of Debentures covered by such registration
statement. No person guilty of fraudulent misrepresentations (within the meaning
of Section 11(f) of the Securities Act), shall be entitled to contribution from
any person who is not guilty of such fraudulent misrepresentation.

          The indemnification of underwriters provided for in this Section 5
shall be on such other terms and conditions as are at the time customary and
reasonably required by such underwriters. In that event the indemnification of
the sellers of Debentures in such underwriting shall at the sellers' request be
modified to conform to such terms and conditions.

          The indemnification and contribution agreements contained herein shall
be in addition to any other rights to indemnification and contribution which any
indemnified party may have pursuant to law or contract or otherwise, shall
remain operative and in full force and effect regardless of any investigation
made or omitted by or on behalf of any indemnified party and shall survive the
transfer of Debentures by any such party.

          6. MISCELLANEOUS.

          (a) This Agreement shall inure to the benefit of an be binding upon
     the successors and assigns of each of the parties, including without
     limitation and without the need for an express assignment, subsequent
     holders of Debentures; PROVIDED that nothing herein shall be deemed to
     permit any assignment, transfer or other disposition of Transfer Restricted
     Securities in violation of the terms hereof or of the Purchase Agreement or
     the Indenture. If any transferee of any holder of Debentures shall acquire
     Transfer Restricted Securities in any manner, whether by operation of law
     or otherwise, such Transfer Restricted Securities shall be held subject to
     all of the terms of this Agreement, and by taking and holding such Transfer
     Restricted Securities such Person shall be conclusively

                                       9




     deemed to have agreed to be bound by and to perform all of the terms and
     provisions of this Agreement, including the restrictions on resale set
     forth in this Agreement and, if applicable, the Purchase Agreement, and
     such Person shall be entitled to received the benefits hereof.

          (b) Any notice or other communications required or permitted hereunder
     shall be deemed to be sufficient and received if contained in a written
     instrument delivered in person or by courier or duly sent by first class
     certified mail, postage prepaid, or by facsimile addressed to such party at
     the address or facsimile number set forth below:

          (1) if to the Company, to it at:

               5080 Spectrum Drive
               Suite 400, West Tower
               Addison, Texas 75001
               Telecopy Number: (972) 387-1938
               Attention: General Counsel

          with a copy to:

               Reboul, MacMurray, Hewitt, Maynard & Kristol
               45 Rockefeller Plaza
               New York, New York 10111
               Telecopy Number:  (212) 841-5725
               Attention: Othon A. Prounis

          (2) if to any holder of Debentures, at the address set forth on the
     records of the Note Register under the Indenture.

          (c) THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE
     WITH THE LAWS OF THE STATE OF NEW YORK.

          (d) This Agreement constitutes the entire agreement of the parties
     with respect to the subject matter hereof and may not be modified or
     amended except by an instrument in writing signed by the Company and (i)
     the holders of a majority of the principal amount of maturity of the
     Debentures and (ii) if adversely affected thereby, each of the other
     holders of Debentures so adversely affected. Any waiver of any provision of
     this Agreement must be in a writing signed by the party against whom
     enforcement of such waiver is sought.

          (e) This Agreement may be executed in two or more counterparts, each
     of which shall be deemed an original, but all of which together shall
     constitute one and the same instrument.

                                       10




          (f) Headings and section reference numbers in this Agreement are for
     reference purposes only and shall not in any way affect the meaning or
     interpretation of this Agreement.

          (g) In the event that any one or more of the provisions set forth
     herein shall, for any reason, be held to be invalid, illegal or
     unenforceable in any respect, such invalidity, illegality or
     unenforceability shall not affect any other provision of this Agreement.

          (h) Except for holders of the Debentures and as specifically set forth
     in Section 5 hereof, this Agreement is not intended to confer any rights or
     remedies upon any person other than the parties hereto.

          (i) Each party hereto agrees that a remedy at law for any breach or
     threatened breach by such party of this Agreement would be inadequate and
     therefore agrees that any other party hereto shall be entitled to specific
     performance of this Agreement in addition to any other available rights and
     remedies in case of any such breach or threatened breach.

          (j) EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES ANY AND ALL
     RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATED TO
     THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

                                       11




          IN WITNESS WHEREOF, each of the parties hereto has executed this
Agreement as a sealed instrument, all as of the day and year first above
written.

                                    CONCENTRA MANAGED CARE, INC.


                                    By:  /s/ Richard A. Parr II
                                         -----------------------------------
                                         Name: Richard A. Parr II
                                         Title: Executive Vice President and
                                                General Counsel




                         WCAS CAPITAL PARTNERS III, L.P.
                         By:  WCAS CP III Associates, L.L.C., General Partner


                            By /s/ Paul Queally
                            -----------------------------
                               Managing Member




                         JP MORGAN DIRECT CORPORATE FINANCE
                         INSTITUTIONAL INVESTORS, LLC


                         By: /s/ Julian E. Shles
                             ------------------------------------
                             Name: Julian E. Shles
                             Title: Vice President of J.P. Morgan Investment
                                    Management, Inc., as Investment Advisor

                         JP MORGAN DIRECT CORPORATE FINANCE
                         PRIVATE INVESTORS, LLC


                         By: /s/ Julian E. Shles
                             ------------------------------------
                              Name: Julian E. Shles
                              Title: Vice President of J.P. Morgan Investment
                                     Management, Inc., as Investment Advisor





                         CALIFORNIA PUBLIC EMPLOYEES'
                         RETIREMENT SYSTEM


                         By: /s/ David E.J. Maxwell
                            -------------------------------------
                         Name: David E. J. Maxwell
                         Title: Principal Investment Officer





                         CALIFORNIA STATE TEACHERS' RETIREMENT SYSTEM


                         By: /s/ Eileen Y. Okada
                             ---------------------------------
                             Name: Eileen Y. Okada
                             Title: Director of Investment Administration
                                    and External Relations





                         CHASE EQUITY ASSOCIATES, L.P.
                         By:  Chase Capital Partners,
                              its General Partner


                         By: /s/ Jonas Steinman
                             ----------------------------------
                             Name: Jonas Steinman
                             Title:




                       CMS CO-INVESTMENT SUBPARTNERSHIP II

                       By: CMS CO-INVESTMENT SUBPARTNERSHIP,
                              a Delaware general partnership
                       By: CMS Co-Investment Partners, L.P., a Delaware limited
                              partnership
                       By: CMS/Co-Investment Associates, L.P., a Delaware
                              limited partnership
                       By: MSPS/Co-Investment, Inc.,
                               a Delaware corporation

                       By: /s/ Richard Mitchell
                           --------------------------
                       Its: Vice President

                       By: CMS 1997 Investment Partners, L.P., a Delaware
                              limited partnership
                       By: CMS 1997, Inc.
                              a Delaware corporatio

                       By: /s/ Richard Mitchell
                           --------------------------
                       Its: Vice President

                       By: CMS Co-Investment Partners I-Q, L.P., a Delaware
                              limited partnership
                       By: CMS/Co-Investment Associates, L.P., a Delaware
                              limited partnership
                       By: MSPS/Co-Investment, Inc.,
                              a Delaware corporation

                       By: /s/ Richard Mitchell
                           -------------------------
                       Its: Vice President

                       By: CMS 1997 Investment Partners, L.P., a Delaware
                              limited partnership
                       By: CMS 1997, Inc.
                            a Delaware corporation

                       By: /s/ Richard Mitchell
                           -------------------------
                       Its: Vice President


                       By: /s/ Ira Brind
                           -------------------------
                           Ira Brind



                      By: /s/ Bruce Lindsay
                           ------------------------
                           Bruce Lindsay


                      CMS DIVERSIFIED PARTNERS, L.P.
                      By: CMS/DP Associates, L.P, a general partner
                      By: MSPS/DP, Inc., its general partner

                                   By: /s/ Richard Mitchell
                                       -----------------------------------
                                                  Vice President

                      By: CMS 1995 Investment Partners, L.P, a general partner
                      By: CMS 1995, Inc., its general partner

                                   By: /s/ Richard Mitchell
                                       -----------------------------------
                                                  Vice President





                          BT CAPITAL INVESTORS, L.P.


                          By: /s/ Heidi Silverstein
                              ---------------------------
                              Name: Heidi Silverstein
                              Title:   Director





                       FINANCIERE ET INDUSTRIELLE GAZ ET EAUX


                       By: /s/ Bertrand Soleil
                           Name: Bertrand Soleil
                           Title:





                       GS PRIVATE EQUITY PARTNERS II, L.P.
                       By: GS PEP II Advisors, L.L.C.,
                                its General Partner

                       By: GSAM Gen-Par, L.L.C.,
                                its Managing Member


                       By: /s/ Jerome Truzzolino
                           -----------------------------
                           Name: Jerome Truzzolino
                           Title: Vice President


                       GS PRIVATE EQUITY PARTNERS II OFFSHORE, L.P.

                       By:  GS PEP II Offshore Advisors, Inc.,
                                its General Partner


                       By: /s/ Jerome Truzzolino
                           -----------------------------
                           Name: Jerome Truzzolino
                           Title: Vice President


                       GS PRIVATE EQUITY PARTNERS II -
                       DIRECT INVESTMENT FUND, L.P.

                       By: GS PEP II Direct Investment Advisors, L.L.C.,
                               its General Partner

                       By: GSAM Gen-Par, L.L.C.,
                                 its Managing Member


                       By: /s/ Jerome Truzzolino
                           -----------------------------
                           Name: Jerome Truzzolino
                           Title: Vice President







                      GS PRIVATE EQUITY PARTNERS III, L.P.

                      By:  GS PEP III Advisors, L.L.C., its
                               General Partner

                      By:  GSAM Gen-Par, L.L.C., its Managing
                               Partner


                      By: /s/ Jerome Truzzolino
                          ----------------------------------
                          Name: Jerome Truzzolino
                          Title: Vice President


                      GS PRIVATE EQUITY PARTNERS III OFFSHORE, L.P.

                      By:  GS PEP III Offshore Advisors, Inc.,
                               its General Partner


                      By: /s/ Jerome Truzzolino
                          ----------------------------------
                          Name: Jerome Truzzolino
                          Title: Vice President


                      NBK/GS PRIVATE EQUITY PARTNERS, L.P.

                      By:  GS PEP Offshore Advisors (NBK), Inc.
                               General Partner


                      By: /s Jerome Truzzolino
                          ----------------------------------
                          Name: Jerome Truzzolino
                          Title: Vice President





                   HAMILTON LANE PRIVATE EQUITY PARTNERS, L.P.

                   By:  HLSP Investment Management, LLC


                   By: /s/ Mario L. Giannini
                       ---------------------------------
                       Mario L. Giannini
                       Managing Member


                   HAMILTON LANE PRIVATE EQUITY FUND, PLC

                   By:  HLSP Investment Management, LLC


                   By: /s/ Mario L. Giannini
                       ---------------------------------
                       Mario L. Giannini
                                Managing Member






                   A.S.F. CO-INVESTMENT PARTNERS, L.P.


                   By: /s/ Jonathan F. Murphy
                       ------------------------------------
                       Name: Jonathan F. Murphy
                       Title: Managing Member of Old Kings I, LLC, the
                              Sole Member of PAF 10/98, LLC, the Sole
                              General Partner of A.S.F. Co-Investment
                              Partners, L.P.




                    NASSAU CAPITAL PARTNERS III L.P.
                    By Nassau Capital L.L.C.,
                    its General Partner

                    By: /s/ John G. Quigley
                        ----------------------------
                        Name: John G. Quigley
                        Title:   Member


                    NAS PARTNERS LLC


                    By: /s/ John G. Quigley
                        ----------------------------
                        Name: John G. Quigley
                        Title:   Member





                   NEW YORK LIFE INSURANCE COMPANY


                   By: /s/ Steven M. Benevento
                       ---------------------------------
                       Name: Steven M. Benevento
                       Title:   Director





                                   SCHEDULE I

                              SCHEDULE I PURCHASERS

NAME AND ADDRESS OF PURCHASER


WCAS Capital Partners III, L.P.

JP Morgan Director Corporate Finance Institutional Investors, LLC

JP Morgan Director Corporate Finance Private
   Investors, LLC

California Public Employees' Retirement System

California State Teachers' Retirement System

CMS Co-Investment Subpartnership II

CMS Diversified Partners, L.P.

DB Capital Partners

Financiere et Industrielle Gaz et Eaux

GS Private Equity Partners II, L.P.

GS Private Equity Partners II Offshore, L.P.

GS Private Equity Partners II Direct Investment Fund, L.P.

GS Private Equity Partners III, L.P.

GS Private Equity Partners III Offshore, L.P.

NBK/GS Private Equity Partners, L.P.

Hamilton Lane Advisors, Inc.

A.S.F. Co-Investment Partners, L.P.

Nassau Capital Partners III L.P.

NAS Partners LLC

New York Life Insurance Company




c/o    Welsh, Carson, Anderson & Stowe
       320 Park Avenue, Suite 2500
       New York, New York 10022
       Attention: Paul B. Queally
       Telecopy: (212) 893-9566





                                   SCHEDULE II

                                CHASE PURCHASERS


NAME AND ADDRESS OF PURCHASER


Chase Equity Associates, L.P.





c/o  Chase Capital Partners
      380 Madison Avenue, 12th Floor
      New York, New York  10017
      Attention:  Eric Green
      Telecopy:  (212) 622-3950

      with a copy to:

      O'Sullivan Graev & Karabell, LLP
      30 Rockefeller Plaza, 41st Floor
      New York, New York 10112
      Attention:  Phillip Isom
      Telecopy:  (212) 408-2420