Montgomery suffered a lower right leg injury during Friday's preseason game at Las Vegas, Phil Perry of NBC Sports Boston reports.
Montgomery attempted to reach the sideline on his own, but he eventually fell back to the turf and was attended to by the Patriots' training staff before needing assistance to get off the field. He then was carted to the locker room. The severity of the injury is unknown, but anything serious would be a blow to his chances of taking on some of the retired James White's change-of-pace role in the offense. Candidates for that job otherwise are J.J. Taylor and rookie sixth-round pick Kevin Harris.