Only if you can prove it was related to sex, race, religion, etc. It's not wrongful termination if your boss simply doesn't like the color shirt you wore that day or didn't like something (and that can be anything) you did.
These guys are going to have to start by establishing that they have not agreed to the process that the league is following. The league is going to claim this is part of the personal conduct sections of the CBA. If the court agrees with the league, the players agreed to the process so thisgoes through Goodell for the appeal. I'm not sure after that if there is another level of appeal.
but I'm sure you're the one with a law degree?