The Royals optioned right-hander Miguel Almonte back to Class AAA Omaha on Tuesday, clearing a roster spot for the activation of left-hander Danny Duffy from the disabled list.
Duffy faced the Seattle Mariners on Tuesday in his first start since sustaining an oblique injury on May 28 in Cleveland.
It was another short stay in the major leagues for Almonte, who was recalled on Saturday after an injury to left-hander Matt Strahm.
Almonte, 24, logged one scoreless inning for the Royals on Saturday in a 10-5 loss to the Minnesota Twins. He has made two appearances for the Royals this season, allowing three runs at Cleveland on May 28.
The Royals continue to carry eight relievers in their bullpen, and veteran Al Alburquerque remains after replacing Eric Skoglund on the roster on Monday.