"Jake Peavy won't be calling the shots in his recovery from a right groin strain, as general manager Ken Williams said Wednesday that Peavy will need at least one minor league rehabilitation assignment before rejoining the Sox.

"No matter what he thinks, he can't simulate the intensity of a game in the bullpen, warming up or during pitchers' fielding practice," Williams said. "You just can't do that. You have to get in the game, have to break toward first base, cover first base. Those are the only things that will test how strong you are getting down in your groin area. That's just the way it is."

Peavy first felt discomfort May 30 in Boston, but he admitted he had trouble covering first base and lasted only four innings Sunday against the Tigers.

Left right for Crain: Reliever Jesse Crain isn't entirely sure how he has limited left-handed batters to three hits in 33 at-bats this season.

"Maybe the biggest thing is that I got pitches that go both ways to left-handers," Crain said. "I can throw my hard slider, which goes in and down with their swing. I haven't used my curve too much, which has been a pretty good pitch.

"Don't know what it is. Maybe the selection and having pitches go both ways makes it tough on them.""