It was Week 5 against the Seattle Seahawks last season, and the Panthers' center had suffered a left foot injury.
"He had the injury, came to the sideline, we taped him and he went back in to play," head athletic trainer Ryan Vermillion said. "He's a tough guy."
After the game, Kalil had his foot further examined, and he learned he wouldn't be able to play through the pain any longer.
Kalil had suffered a Lisfranc injury. His season was over.
"We were hoping for a cast for a couple weeks and then get him back in," Vermillion said. "We were all surprised. That was the first kick in the teeth."
Kalil had never missed any significant time due to injury in his football career. Suddenly, an injury he briefly played through was going to force him to injured reserve and require months of rehabilitation.
"When you go that long in your career without having to deal with that – I don't want to say you think you are invincible – but you tend to forget that's part of the game," Kalil said. "It was like all the (emotional) stages they talk about."
Thirteen months later, Kalil has been voted the Panthers 2013 Ed Block Courage Award winner by his teammates. He is once again anchoring the Carolina offensive line, starting all 12 games so far this season.
"It's been great to have Ryan back," head coach Ron Rivera said. "There's a comfort level you have with very, very good players."
Like a lot of players, Kalil finds comfort in routine. But now he's dealing with a completely new routine in addition to the discomfort that comes with a healing foot.
"Football players in general love routines," Kalil said. "My offseason was a different routine, getting ready for the season was different, getting ready before practice was different. It took longer doing different tape jobs and more maintenance."
Kalil may be back on the field performing at the high level the three-time Pro Bowler is accustomed to, but he's still managing the pain that comes with Lisfranc recovery on a daily basis.
"To this day the foot still hurts. It still gets sore. He still has pain issues with it," Vermillion said. "He can play and he does everything fine, but he still comes in every day to get treatment, he still does the extra warmup and has to ice it after practice."
Vermillion said it takes about 18 months post-surgery for the pain to disappear.
In the meantime, Kalil will continue to diligently manage the treatment required to keep the swelling and soreness to a minimum. That way when he takes the field he can perform at his best without any limitation.
"He looks like he is right where he needs to be," Rivera said. "Without a doubt in my mind."