Oakland Athletics pitcher Brett Anderson left Wednesday's start against the Detroit Tigers in the third inning with a right oblique strain.
Anderson gave up a two-run double to Omar Infante before back-to-back walks loaded the bases for Delmon Young.
On a 2-1 pitch to Young, Anderson slipped on his follow through and appeared to injure himself.
The training staff came out to check on the left-hander, and after a brief meeting, he exited toward the dugout as Pat Neshek came in from the bullpen.
Anderson entered play on Wednesday with a 4-1 record and a 1.93 earned run average over five starts this season.