Johnny Knox looks like he’s in game-shape when he appears in the dimly-lit entrance of a Chicago hotel restaurant Wednesday morning. Except the always lean receiver walks with a limp, and he struggles to sit or stand comfortably, the lingering effects of a devastating hit he endured at Soldier Field 13 ½ months ago. Yet Knox counts his blessings and not his challenges, even as he exclusively tells the Sun-Times that his football career is over. “As an athlete, you don’t want to give up, you want to keep on fighting. That’s how I’ve always been,” Knox says. “But it’s been on my heart for a while. I know how my body feels, and I know I’m not going to be the same and perform at the ability that I used to. “So I’m moving on and going forward.” That’s a “hard pill to swallow” for the 26-year-old who prided himself on his underdog story, one that started at Tyler Junior College in 2005 and culminated with a Pro Bowl trip to Hawaii as a kickoff returner just five years later. He flashed his potential as a receiver during the 2010 season, finishing just 40 yards shy of 1,000, and he regained his starting spot after the club tabbed Roy Williams as a starter in 2011.