Fred Jackson hasn't filed his retirement paperwork with the NFL because the 36-year-old believes he can still play despite going unsigned last season.

"I want to play, but it's one of those things where we'll see what happens," Jackson said. "Training camps are around the corner. Some teams lose a back or two and maybe they give me a call. We'll see what happens. I'm not ready to hang 'em up yet, but I do know that I'm 36 and a lot of teams are scared of that."

Jackson was one of the NFL's slowest running backs in 2015, which limited him to pass protection and checkdowns with the Seattle Seahawks.

John Riggins and Marcus Allen are the only running backs in NFL history to rush for 300 yards in a season at age 36 or older.