The Chicago Bears announced Wednesday they terminated the contract of receiver Johnny Knox, who missed the entire 2012 season after suffering a back injury in 2011 that required surgery to stabilize a fractured vertebra.

A vested veteran, Knox started in 27 of 45 games from 2009-11 with the Bears, catching 133 passes for 2,214 yards and 12 touchdowns. Knox was in the final year of his contract and received $1.26 million despite spending the entire 2012 season on the physically unable to perform list.

Despite working diligently to rehabilitate, Knox never recovered sufficiently enough to make a return to the team. Multiple sources expressed doubt that Knox will ever return to form given the severity of his injury.

Knox underwent spinal fusion surgery to stabilize his fractured vertebra on Dec. 19, 2011, and the initial prognosis was that it would take approximately six months just to recover enough for him to begin rehabilitation for a return to the football field. The injury was more severe than originally anticipated, and it was later discovered Knox suffered from some nerve damage.

When the Bears convened at Halas Hall last spring for workouts, it became clear Knox would face a difficult recovery. Knox admitted to losing 30 pounds of muscle, and the nerve damage caused the receiver to walk gingerly. Throughout the 2012 season Knox appeared to have regained some of the muscle had had lost, but he still wasn't yet walking normally, which led to doubt about whether he'd ever return to form as one of the club's speedier receivers.

In July, Knox said "there's really no timetable" for a full recovery and added, "I'm still working. I don't have that same burst that I used to have. But that's to be expected with this injury. I'm jogging, moving around pretty good."

Knox suffered the injury during the Bears' Dec. 18, 2011 loss to the Seattle Seahawks at Soldier Field on a devastating hit from defensive end Anthony Hargrove that bent the receiver back at an awkward angle.

Catching a pass across the middle, Knox attempted to turn up the field, but safety Kam Chancellor knocked the ball out of the receiver's grasp.

As Knox attempted to turn back to pounce on his fumble, Hargrove dove for the ball, causing a vicious collision that left the receiver lying on the grass at Soldier Field writhing in pain for several minutes.

Knox recalled the experience as "frightening" back in July, but was optimistic about what he expected to be an eventual return to the Chicago Bears.

"Right now, I'm setting small goals, taking it a little bit at a time," Knox said. "At first, I knew it was gonna be hard to run. But now, I'm running better than I thought I would, getting my weight back a little more, doing heavier weights in the weight room. So I'm doing good. Honestly, (there have) been days where I've been down. But for the most part, I always stay positive, stay motivated. That's why I'm out here today getting better. It means a lot to me (to be around teammates). Even though I'm injured, I'm so excited to come down here and be around the guys all day, every day, and just focus on just strictly rehabbing."

Former Bears receivers coach Darryl Drake, who is now with Arizona, was asked recently if he thinks Knox will play again.

"I don't know," Drake said on "The Waddle & Silvy Show." "I know he's working extremely hard. I think that's in God's hands. You never say never, you never know. Will he get there? I just don't know. I hope he does, because I think he's a special talent."

Knox averaged 16.6 yards per catch during the three seasons he played with the Bears, which ranked as the seventh-best average in the NFL over that span.

Knox earned Pro Bowl recognition as a rookie kick returner in 2009, and over his career returned 55 kickoffs for 1,506 yards.