Red Sox manager Terry Francona said before Saturday night's game against Tampa Bay that Youkilis, who returned to Boston on Friday for an MRI exam, will miss the final two games of the weekend series with the Rays.
"He stayed back," Francona said. "He's a little sore. We'll see where he's at Tuesday."
Boston opens a homestand Tuesday night against Toronto.
Youkilis received an injection for his sore hip Friday.
Francona added Youkilis has had the onset of a sports hernia and that it will be evaluated after the season.
"It's kind of a general term which means he has a weakening of an area, which we already knew," Francona said. "For now, they believe he can play. If we need to give him a day off, we can certainly do that."
Also, right-hander Josh Beckett, out with a sprained right ankle, threw long toss and at 60 feet on level ground.
"He's doing pretty good," Francona said. "We'll continue to re-evaluate him and see how he does."
Francona said no date has been set for Beckett to throw off a mound. Left-hander Erik Bedard, who has a lat muscle strain, has not yet resumed throwing.
"He's improving," Francona said. "The one thing we don't want to do is try to rush him back. The timetable isn't really set in stone. It's how he feels, and I don't think he thinks he needs a whole lot [of time] once he feels good."
John Lackey has a sore left calf after being hit by a batted ball during his start Friday night. The Red Sox believe the right-hander could make his next scheduled start on Wednesday.