Montgomery won't return to Friday's preseason game in Las Vegas due to a right ankle injury, Phil Perry of NBC Sports Boston reports.
In a game in which Damien Harris (undisclosed) didn't play, Rhamondre Stevenson got all the backfield reps on the Patriots' first possession, with Montgomery entering on the team's second drive. After his only official touch (a four-yard carry), Montgomery was tended to by New England's training staff before requiring assistance to reach the sideline and a cart to go to the locker room. He's the top candidate to take on a share of the retired James White's vacated change-of-pace role this season, but a serious injury could impact those plans. Rookie fourth-rounder Pierre Strong, J.J. Taylor and sixth-rounder Kevin Harris likely are the next players up if Montgomery misses any time.