It's always a given: Each and every offseason there are always some players that are a bit disgruntled about their contracts. There's no way around it.
Now why do we see so much of this in the NFL? Simple: There's not a lot of guaranteed money being thrown around like there is in Major League Baseball or other sporting leagues.
In that spirit, let's take a look at 20 NFL players who are most likely to complain about their contract next offseason.