Martinez exited Sunday's game against the Astros early with back spasms, Jason Mastrodonato of the Boston Herald reports.
Upon leaving the game, Martinez was shown pointing to his back while talking to the team trainer. It was later revealed that he was suffering from back spasms, although manager Alex Cora stated he doesn't believe it's a big issue, and Martinez is expected to play Tuesday. He was lifted and replaced by Sam Travis, who hit a two-RBI single in the ninth inning.