Every once in a while, even a superstar athlete in the NFL suffers from a down year.
The true superstars will rebound in the following year, while others fade away and aren't heard from again.
Last year, Chris Johnson flopped big time after a contract dispute all offseason. Jamaal Charles suffered a torn ACL and missed the entire season.
It's a tough thing to project. Johnson looked unstoppable in 2010 before his less-than-stellar 2011 season.
That's the reason why they are superstars. They've proven over a series of seasons they can get it done.
Here's a look at some superstars in the NFL who have the potential of struggling in 2012 for different reasons.