McCullers (7-3) allowed five runs on eight hits, four walks and two hit batsmen over five-plus innings in Sunday's 13-1 loss to the Tigers.
McCullers continued a frustrating stretch in which he's posted a 7.45 ERA in six starts since coming off the disabled list in late June. He faced 28 batters Sunday, 13 more than the minimum for a five-inning start. He was able to navigate a few jams and kept the game close, but manager A.J. Hinch had seen enough after the right-hander put the first two men of the sixth inning on base. McCullers is next due to start Friday at home against the Blue Jays.