Martinez will serve as designated hitter and bat cleanup against the Athletics on Saturday, Sean McAdam of BostonSportsJournal.com reports.
Martinez received the day off Friday after being lifted for a pinch runner late in Thursday's game, but there was never any indication of an injury. The 30-year-old will look to continue with his hot bat, as he's 13-for-24 with three doubles, two home runs and five RBI over his last six games.