Montgomery (7-7) took the loss in the second game of Wednesday's doubleheader against Cleveland, allowing four runs on six hits and three walks over four innings while striking out five.
The lefty needed 92 pitches (58 strikes) to record just 12 outs as his second-half struggles continue. Montgomery now has a 5.35 ERA in 38.2 innings since the All-Star break, but he will likely move to the bullpen in September barring another injury to one of the Yankees' veteran hurlers.