Kolb only attempted four passes before leaving with a head injury on Saturday.(Patrick Smith/Getty Images)
Kevin Kolb's last concussion, which the Buffalo quarterback suffered Saturday in a loss to the Redskins, could put his football future in jeopardy. Tim Graham of the Buffalo News reports that the "Bills [are] concerned Kolb's concussion may be career-ending and they're proceeding with that in mind."
With Kolb leaving this week's game and rookie -- and presumptive starter -- E.J. Manuel out for the remainder of the preseason with a knee injury, the shorthanded Bills signed QB Matt Leinart on Sunday. Leinart, Jeff Tuel and Thaddeus Lewis will serve as Buffalo's quarterbacks in its preseason finale against Detroit.
Kolb, 29, has had issues with concussions since entering the league. A similar injury sidelined him in both 2010, when he was with Philadelphia, and in 2011, when he was the starter in Arizona.
The Bills could place Kolb on injured reserve with the designation to return -- each team gets to bring one player back from I.R. during the season, per a rule implemented last year.
Buffalo remains hopeful that Manuel will be ready in time for Week 1 of the regular season, after undergoing a minor knee procedure. He and Kolb had been competing for the starting QB job in rookie coach Doug Marrone's fast-paced offense, with Manuel taking the lead before sitting out the past week.
Kolb, signed a two-year contract by the Bills in March, and had a chance to state his case against the Redskins this weekend. He only attempted four passes, though, completing two, before leaving with his head injury.