From what I read on the CBS live game blog, he pulled up on the way to first base, then stayed in the game after the trainers looked at him. After they got out of the inning, he didn't return on defense. Seems like a precautionary thing, and he probably won't miss more than a game, if anything.
10-Team H2H Std. 5x5
R. Martin, G. Atkins, J. Rollins, A. Hill, D. Wright, A. Gordon,
E. Renteria, Crawford, M. Ramirez, P. Burrell, N. Markakis, C. Hart
Lincecum, J. Cueto, H. Street, G. Sherrill, M. Capps, AJ Burnett, Putz, B. Myers, Harden, Bedard,