In fifth inning against the Marlins on Friday night, Phillies right-hander A.J. Burnett, after delivering a pitch to Casey McGehee, exited the game with what the team later called "groin soreness." There's no word yet on the severity.
In a perhaps related matter, Burnett struggled with his command all night, as he spotted just 54 of 106 pitches for strikes. On the season, Burnett has a 3.94 ERA after two starts (counting Friday night's), but he's walked 14 batters against just 10 strikeouts in 16 innings of work.
Given Burnett's complete lack of command against the Marlins, it's possible that his discomfort was affecting his mechanics.