No lump sum agreement made prior to the establishment of liability for compensation shall prohibit an employee from subsequently filing a claim for medical benefits only, in any instance in which such employee has suffered a substantial deterioration of his medical condition which (i) could not reasonably have been foreseen at the time said agreement was entered into, and (ii) is the result of an injury for which the insurer would have been liable under this chapter, absent the lump sum settlement. Claims under this paragraph shall be considered only if brought within one year of the date the employee first became aware of the causal relationship between the substantial deterioration and the employment. Claims shall be consistent with the procedures set forth in sections ten, ten A, and eleven. No liability for such claims shall be redeemed by any additional lump sum settlement; provided, however, that no employee shall be entitled to vocational rehabilitation benefits for any injury, unless such employee shall have requested such benefits within two years of the perfection of any settlement under this section of benefits due for said injury.
Notwithstanding any provision of this section or of sections seventy-five A or seventy-five B, the acceptance of any amount in return for the right to claim future weekly benefits shall create a presumption that the employee is physically incapable of returning to work with the employer where the alleged injury occurred. Such presumption shall continue for a period of one month for each fifteen hundred dollar amount included in the settlement for future weekly benefits. No re-employment rights shall inure to such employee under this chapter during any period of presumption of incapacity as herein provided.
Mass. Gen. Laws ch. 152, § 48