A dislocated knee cap is VERY serious. You typically wind up tearing everything (tendons, ligaments, cartilage) in the joint.
This could easily end his career or dramatically limit his ability to play.
I can't run anymore, no basketball, can't hang off the dogsled getting whipped around bends, and forget about any sideways bends of knees. I can still hunt above treeline with brace on and guess I am thankful for that. Everyone should wear those elastic knee supports with age. Sure would beat the limitations ACL damage inflicts.
Sad, but if anyone thinks Palmer will be the athlete he once was; wishful thinking. A future of reinjuries as long as he plays the game.