Farrell was optioned to Triple-A Omaha on Sunday, MLB.com reports.
Farrell was just making a spot start for Game 1 of Saturday's doubleheader with the Twins, and after he was lit up for five runs in 2.2 innings, it was an easy decision for the Royals to drop him from the 25-man roster. The right-hander should have a rotation spot waiting for him upon returning to Omaha, with whom he had posted at least nine strikeouts in three of his last four starts.