Keys left Tuesday's practice session after sustaining a leg injury and did not return, Joe Buscaglia of The Athletic reports.
Keys sustained the injury during one-on-one drills at practice. He played 15 snaps (14 on offense, one on special teams) in Saturday's 33-6 preseason loss to the Bears, finishing with one catch for 13 yards. The undrafted rookie out of Tulane is a long shot to make the Bills' final 53-man roster, and missing preseason games would hurt his chances even more.