Buffalo Bills quarterback Kevin Kolb suffered a "serious" concussion during his side's pre-season loss to the Washington Redskins on Saturday, according to reports.
Kolb was forced off in the first quarter after receiving a knee to the head when diving for a first down, although he remained on the field for the final four plays of the drive before eventually being taken off.
According to ESPN, the Bills are approaching the injury as a potentially career-ending one for the 29-year-old due to his history of concussions, having also missed time with similar injuries in 2010 and 2012.
Kolb had been embroiled in a battle for the starting quarterback jersey with EJ Manuel, but the Bills could be without both for their regular season opener after Manuel underwent a minor surgical procedure on his knee last Saturday.
Bills coach Doug Marrone has moved to address the lack of fit quarterbacks, bringing in veteran Matt Leinart and trading with the Detroit Lions for Thaddeus Lewis.
