Many things can go wrong with NFL players. Injuries happen, skills regress and mechanical flaws develop. Other times, players need a simple confidence boost.
It's easy to spot players in need of a confidence boost. They are typically talented and often have a history of success, but they simply aren't playing as well as they can.
This applies to every one of these players. Confidence may not be the only issue with them right now, but it is a significant one.