The Bills made the signing of running back Reggie Bush official Monday afternoon and also announced three other roster moves.
Wide receiver Kain Colter was signed, and kicker Marshall Morgan and wide receiver Davonte Allen were released.
The release of Morgan leaves Dan Carpenter as the only kicker in camp. In swapping Colter for Allen, the Bills have 10 active wide receivers on their camp roster with Sammy Watkins, Marcus Easley and Kolby Listenbee not yet cleared.
Colter was a quarterback and wide receiver at Northwestern, where he led an attempt to create a union for college players and give them the opportunity to collectively bargain as employees.
Colter broke into the NFL in 2014 with the Vikings and spent some time on their practice squad. He spent some time with the Rams earlier this season.