"I'm not going to put a timeline on it," Bay said. "I politicked to get in there in [St. Petersburg], too, and then I ended up right back here. Hopefully I'm not more than a couple days away."
In his absence Saturday, Kevin Youkilis started for the second time in three games in left field.
Bay, who has played just once since leaving last Saturday's game with a cramp in his right hamstring, aggravated the muscle Wednesday running out a routine ground ball vs. the Rays. He tested the hamstring with a running program before Saturday's game and reported no problems, though Bay remained uncertain whether or not he could play in Sunday evening's finale at Yankee Stadium.
"How bad do you want to push it?" Bay said. "I'd love to, but that being said, if we're trying to be smart about it, I just don't know."
Bay is batting .252 with 21 home runs and 75 RBIs in 102 games, the vast majority of that damage coming before the All-Star break.
"He says he's feeling a lot better," Red Sox manager Terry Francona said. "Which is great news for us."
Anthony DiComo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.