Lugo downplayed the injury after the game, saying he'd be ready to play in Sunday afternoon's game, but Red Sox manager Terry Francona, who said he thought the injury was "more of a hip flexor," didn't seem to agree with his optimistic infielder.
"We'll reevaluate him in the morning and stay away tomorrow," Francona said.
Lugo who went 1-for-2 and made a key defensive play in the fourth inning of the 5-3 win over the Mariners, said the injury did not happen in Saturday's game.
"It's something that's been sore for a few days, but it's no big deal, man," Lugo said.
Francona, however, said Lugo told him that the groin was "grabbing" on him during the game. Lugo was replaced by Gil Velazquez, who likely will get the start Sunday.
Doug Miller is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.