The bill, which passed both houses by large margins, denies parole to some offenders after they have been convicted a third time. In his message to legislators, Patrick said judges should be able to make exceptions, allowing some habitual criminals who would otherwise be subject to the law to be released after they have served two-thirds of the sentence or 25 years for lifers, The Boston Globe reported.
Some earlier versions of the bill included the "safety valve," although the final draft did not. A number of legislators during debate called for its return.
The House and Senate must act before the session expires Tuesday; Patrick said he will sign the bill next week if legislators adopt the change.