Thornton (1-5) took the loss Tuesday at Baltimore after giving up three runs on seven hits over five innings. He struck out four and walked three.
Thornton issued three walks in his fourth straight start as free passes continue to be a major hurdle for the right-hander. The 25-year-old has a 4.78 ERA, 1.41 WHIP and 73:34 K:BB through 69.2 innings and has a daunting matchup Sunday at Houston.