"He jammed it a bit," Yost said. "We won't put him in a game until he's 100 percent."
Coleman is trying to secure a spot in the Royals' bullpen. He divided last season between Kansas City and Triple-A Omaha, compiling a 0.61 ERA in 27 games for the Royals.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.