Olsen missed the first month of spring training camp with a strained left hamstring and has struggled in two relief outings. He has a 15.43 ERA and has allowed seven base-runners in 2 1/3 innings.
"The ball is just not coming out of his hand the way it was before the hamstring injury," general manager Neal Huntington said Monday.
With Olsen out, right-hander Charlie Morton has all but clinched the final open spot in the rotation. In four games, Morton has a 1.29 ERA with eight strikeouts in 14 innings.