It is sometimes hard for NFL players, and there are some Buffalo Bills players who could fall into this category, to hang the cleats up. There may even be some desire to return to the game after some time has passed, and they realize they still have some left in the tank.
Every offseason, there are players that will try to make a comeback or believe they can return to the game, for example what felt like the never-ending saga with Brett Favre a few years back. This offseason there was rumors that former Bills wide receiver Percy Harvin was trying to make a comeback.