Angels starting pitcher Garrett Richards left in the first inning of Monday's game against Texas with a strained right groin.
Richards, 23, was making his second career start and gave up an unearned run while recording two outs. He left after Michael Young singled, and Bobby Cassevah took over.
The right-handed Richards made his first start last Wednesday against the Yankees, after his contract was selected from Double-A Arkansas. He gave up six runs during that five-inning outing.