Coach Sean McDermott told reporters Tuesday that both Tyrod Taylor and T.J. Yates remain in concussion protocol.
Taylor exited the team's third preseason game Saturday after getting his head slammed to the turf on a sack.
The Bills head into Thursday's preseason finale with rookie Nathan Peterman and newly signed Keith Wenning as the only two healthy quarterbacks on the roster. McDermott noted he's mindful of exposing Peterman in the fourth preseason game, as the fifth-round pick could be the starter Week 1, per Chris Brown of the team's official website.
In other Buffalo injury news, McDermott said he's cautiously optimistic receiver Jordan Matthews will be ready for the season opener. Matthews has been limited in practice with a chest injury and has not been cleared for full contact.
Other injury news we are tracking on Tuesday:
- NFL Network Insider Ian Rapoport reports that Tennessee Titans wide receiver Corey Davis (hamstring) is expected to be ready for Week 1. Davis and fellow wideout Eric Decker (ankle) both returned to practice on Tuesday.
Harbaugh added he's "optimistic" wide receiver Breshad Perriman (hamstring) will be ready to play by Week 1.
- Detroit Lions general manager Bob Quinn expects defensive end Ezekiel Ansah (ankle) to be ready for Week 1 of the regular season.
- Oakland Raiders rookie Gareon Conley (shin) is practicing and off the PUP list. He is expected to be ready by Week 1 after dealing with serious shin splints.
- Jay Gruden confirmed that Washington Redskins defensive lineman Phil Taylor Sr. will miss 2017 season with torn left quad.