Kansas City, Mo. ? The Kansas City Royals put pitcher Jeremy Affeldt on the 15-day disabled list Sunday and recalled pitcher Justin Huisman from Triple-A Omaha.

Affeldt could miss up to two months with partially torn muscles in his rib cage, an MRI revealed Sunday. The left-hander was injured while pitching in the ninth inning against St. Louis on Saturday.

“Usually it’s two weeks before he gets the pain down on an injury like this,” trainer Nick Swartz said. “He’ll be out four to six weeks. But then he’s got to take two weeks to get ready to play. With a guy like him who throws hard, he’s going to need that time.”

Affeldt had converted eight of 10 save opportunities since moving to the bullpen.

Huisman was 2-2 with three saves and a 3.60 earned-run average in 16 games at Omaha. In seven games with the Royals this spring, he was 0-0 with one save and a 6.75 ERA.