Mass. Gen. Laws ch. 32 § 14A
Third Party Recovery. If a member or beneficiary entitled to a pension under the provisions of section six, seven or nine, also has a right to recover lost wages from any party other than his employer by reason of the same injury or death of such member, the amount of any such recovery for lost wages shall be offset against and payable in lieu of any pension payable on his account under the provisions of said sections according to a schedule approved by the actuary which is consistent with that set forth in paragraph (c) of subdivision (1) of section fourteen. If any such member or beneficiary neglects or fails to prosecute fully such right, the board shall prosecute such right on the member's behalf. In the event the member or beneficiary fails to cooperate with the board in its prosecution thereof the board may, during the period of such failure, suspend such member's or beneficiary's right to further payment under the provisions of section six, seven or nine.
Mass. Gen. Laws ch. 32, § 14A