Bills' Karlos Williams in concussion protocol, status uncertain for Sunday

The Buffalo Bills could be without rookie running back Karlos Williams Sunday against the Tennessee Titans.

General manager Doug Whaley told WGR 550 sports radio Tuesday morning that Williams suffered a concussion in the Bills' Week 4 loss to the New York Giants and is now going through league protocol.

Whaley described Williams as "day to day."

With the uncertain status of Williams and LeSean McCoy, the Bills have just two healthy backs (Boobie Dixon and Cierre Wood) available at the moment.

Whaley said they plan to work out some running backs and called Bryce Brown, a former Bill, "a possibility."