The Royals placed Marsh on the 15-day injured Thursday with a right elbow contusion.
Marsh departed early in his start in Wednesday's 3-2 win over Toronto after being struck in the right elbow by a comebacker. X-rays came back negative on Marsh's elbow, and though he sustained nothing more than a bruise, the Royals decided it was best to shut him down for the next 15 days. The Royals called up Will Klein from Triple-A Omaha on Thursday to give the bullpen a fresh arm in the short term, but it's not immediately clear who will replace Marsh in the rotation.