Rupe was designated for assignment on May 12 after Blake Wood was called up. After appearing in 11 games this season, Rupe was 1-1 with an ERA of 5.59.
This is Rupe's first season with the Royals after spending his previous four with the Texas Rangers.
Samuel Zuba is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.