Kansas City Royals relief pitcher Justin Grimm (back) is close to going out for a rehab assignment, according to manager Ned Yost. Grimm threw a bullpen session on Tuesday, and Yost told reporters that the session went "great." Grimm has given up 17 runs in seven innings this season. He should be back in the Royals bullpen before the end of May, but belongs on the waiver wire in all fantasy leagues.