Baltimore ? Orioles left-hander Adam Loewen will be sidelined for much of the season because of a stress fracture in his pitching elbow, a rare injury that further decimates a starting rotation already in disarray.

Loewen was placed on the 15-day disabled list Friday. He last pitched Tuesday in Detroit, going five innings before leaving with pain in his forearm, elbow and biceps. After an MRI exam and a bone scan, the injury was determined to be in his elbow.

Loewen is 2-0 with a 3.56 earned-run average in six starts.