Montero was optioned to Triple-A Las Vegas on Friday.
Montero has been nothing short of terrible during his time in the majors, sporting an 8.24 ERA after Thursday's debacle. He'll head back to the minors to work out the kinks, although it's unlikely that he'll find his way back to the majors anytime soon with Seth Lugo (elbow), Steven Matz (elbow) and Tyler Pill all vying for rotation spots.