The Buffalo News' Tim Graham reports the Bills fear Kevin Kolb's concussion may end his NFL career. "And they're proceeding with that in mind," Graham writes. It's really not surprising because Kolb has suffered numerous NFL concussions and become increasingly slow to recover. The Bills are left with Matt Leinart, UDFA Jeff Tuel, and Thad Lewis behind E.J. Manuel, who is also on the shelf with a knee scope. The Bills are going to end up rushing back Manuel, in all likelihood, to start Week 1. Kolb signed a two-year, $6.1 million contract in March that contained $1 million guaranteed. He's likely headed for injured reserve.