Danny Duffy will be recalled from Triple-A Omaha on Wednesday to replace Wade Davis in Kansas City's starting rotation.
Duffy has allowed four runs over his last 22 innings in Omaha while recovering from elbow surgery. The lefty made two starts for the Royals this month, allowing two runs over 9.2 innings.
Davis has allowed 11 runs in his last two starts and will move to the bullpen. Since coming to Kansas City in the trade that sent top prospect Wil Myers to Tampa Bay, Davis is 6-10 with a 5.67 ERA.
Duffy will start Wednesday's game against the Minnesota Twins, bumping Bruce Chen back to Thursday.
The Royals also signed Carlos Pena to a minor-league contract and traded for minor league right-hander Clayton Mortensen.