Good news for the Panthers, though, as Joe Person of the Charlotte Observer reports that Johnson's injury is just a sprained MCL.
Johnson's status, per Person, is up in the air for Week 12 in Miami when the Panthers and Dolphins meet.
Panthers coach Ron Rivera wouldn't call the leg whip by Cannon "dirty" but he wasn't happy about it and referred to it as a "disappointing play."
"I'm pretty adamant about it because it happened to me when I played. And I actually fractured my leg and sprained my anterior cruciate," Rivera said. "So whenever I see one of those, it really disappoints me. I know the league is aware of it, mostly because everyone in America saw it last night. So the league will handle that situation."
Johnson was back on the field for Carolina's final defensive drive but he missed substantial time after the injury. He was also in a lot of pain on the field before being carted off.
The Panthers certainly dodged a bullet though -- it looked at first glance that Johnson suffered a pretty catastrophic injury.