Doug Marrone unsure of Kevin Kolb future

Doug Marrone has admitted that he does not know whether Kevin Kolb will be returning to the Buffalo Bills in 2014.

The quarterback missed the entire 2013 campaign after sustaining a concussion in the pre-season, leading to reports that the 29-year-old was considering retirement.

The head coach told WGR-AM: "He's under contract and I'm not aware of really what exactly is going on right now, whether he's planning to come back, whether he's not going to come back. I have not been informed of anything to that nature."

Kolb joined the Bills after being released by the Arizona Cardinals last off-season.