
Allen has had mixed results to open the season, leading Buffalo to a 3-1 record while throwing for 903 yards, three touchdowns and six interceptions. He also has three rushing touchdowns.
Allen was injured on a helmet-to-helmet hit from New England cornerback Jonathan Jones.
Backup Matt Barkley was ready to start if needed and completed 9 of 16 passes for 127 yards and an interception after replacing Allen against New England. Barkley is the only other quarterback on Buffalo's roster, though the Bills have Davis Webb on their practice squad. Buffalo has an open roster spot after releasing tackle Conor McDermott on Thursday.
The Bills filled their open roster spot by promoting former Canadian Football League receiver Duke Williams off their practice squad. Williams spent the past two seasons with the Edmonton Eskimos and led the CFL with 1,579 yards receiving last year.