Montero (5-11) allowed five runs on seven hits and a pair of walks over just four innings in Wednesday's loss to Miami.
The 26-year-old righty has now failed to last longer than 5.1 innings in four consecutive starts since his stunning 8.1 shutout frames against the Reds back on Aug. 30. He's still usually missing some bats, but Montero's issues with command and control sprout up in almost all of his starts, making him practically unusable for fantasy purposes.