Bills coach Sean McDermott offered no update after the game on the severity of McCarron's injury, telling reporters the team "will know more as we get to Buffalo tomorrow."
McCarron started the game and played four series, all of which were three-and-outs, before exiting for rookie gunslinger Josh Allen. He went 3-for-6 for 12 yards with a 56.3 passer rating.
The injury to McCarron alters the quarterback landscape in Buffalo. The fifth-year veteran has been battling for the starting position with the rookie Allen and second-year player Nathan Peterman. McCarron and Peterman split most of the first-team reps during training camp with Allen playing with the third string.
In the preseason opener against Carolina, the Bills' quarterback order went Peterman, McCarron, Allen. But on Friday night, Buffalo switched it up, starting McCarron before bringing on Allen and then Peterman in the second half.