Free agent Johnny Knox has decided to retire from football, telling the Chicago Sun-Times he's "moving on and going forward."

It's a sad end to a once promising career. According to the Sun-Times, Knox is still walking with a limp 14 months after his spinal fusion operation, and "struggles to sit or stand" comfortably. "I was centimeters away from being paralyzed, so just sitting here and talking, I'm appreciative of that," Knox said Wednesday. "Just the hard work that I had to put in. Just to be able to stay in and do everything in my daily life that I used to do." Only 26 years old, the former fifth-round pick ends his career with 133 catches for 2,214 yards and 12 touchdowns over 45 games.

Free agent Johnny Knox's agent says he plans to play in 2013.

"He's going with the mindset that he's playing in 2013," Knox's agent said. Knox is still recovering from the spinal fusion operation he underwent in December 2011, and has an "important physical assessment in late March." Knox is easy to root for, but is facing long odds of returning to the football field in 2013.

ESPN Chicago confirms that Bears WR Johnny Knox will be an unrestricted free agent this offseason.

We read in-season speculation that Knox's salary would "toll" to 2013 because he spent 2012 on PUP, but that won't happen. After missing all of 2012 with a fractured vertebrae in his back, Knox's health status is the biggest concern for his market appeal. The 26-year-old is a quality deep threat when healthy.