Thompson (3-3) took the loss Saturday as the Cubs fell 4-2 to the Royals, giving up two runs on five hits and two walks over four innings. He struck out one.
Called up earlier in the day, the 26-year-old turned in a workmanlike effort, tossing 46 of 73 pitches for strikes before leaving the game with Chicago in a 2-0 hole. Thompson has pitched well in the majors overall this season with a 2.42 ERA and 44:24 K:BB through 44.2 innings, but he could shift back to the bullpen when Adbert Alzolay (hamstring) is ready to return.