On Sunday during practice, Buffalo Bills quarterback AJ McCarron suffered what appeared to be a lower-leg injury that caused him to need medical attention.

Matt Parrino of New York Ustate noted that McCarron was “visibly upset” down in the end zone after what seemed to be a leg injury.

McCarron is currently fighting for the starting quarterback spot, battling Nathan Peterman, and to a lesser extent rookie Josh Allen, for the job. On Thursday night during the first preseason game, McCarron had a fine outing but was overshadowed by Peterman, who clicked with Kelvin Benjamin in a big way on the game’s opening drive.

Needless to say, an injury would be detrimental to him winning the job.