McCullers (2-1) gave up five runs on seven hits and three walks while striking out five over five innings in Wednesday's 7-6 loss to Cleveland.
The right-hander struggled to command the strike zone in this one, throwing 55 of 90 pitches for strikes, and it was the first time this season McCullers didn't strike out at least twice as many batters as he walked. His next start will come Monday at home against the Rangers.