The Royals have placed outfielder Alex Gordon on the disabled list with a strained groin and reinstated right-hander Yordano Ventura to start Thursday's series finale against Tampa Bay.
Kansas City also optioned right-hander Aaron Brooks to Triple-A Omaha and recalled left-hander Brandon Finnegan from the same club.
Gordon was injured while tracking a fly ball in the fourth inning of Wednesday night's win over the Rays. He crumpled to the field near the warning track and lay there for several minutes, eventually needing a cart to leave the field. He later underwent an MRI.
It was still not known how long the All-Star would be out.
Ventura has been on the disabled list with ulnar neuritis, a condition that caused numbness in his pitching hand.