Leach had been a reliever, but the club believes with his four-pitch repertoire he might be able to make the switch. Calero started the season at Triple-A Buffalo in the Mets organization but was released on May 16 after going 2-0 with a 10.59 ERA in 10 games. He spent most of last season in the big leagues with Florida.
The Dodgers also promoted Alberto Bastardo from Chattanooga to take Leach's place in the rotation and placed Scott Elbert on the temporary inactive list as he attends to a family matter.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.