19. Greg Hardy
Hardy earned his place as a regular NFL starter for the Carolina Panthers, making the Pro Bowl in 2013. But then along came his domestic violence case and he became untouchable. When Jerry Jones thinks a player isn’t good news, it says a lot. Meanwhile, he was a pernicious influence in the locker room so the Cowboys let him go.
After leaving the NFL, Hardy decided to become a professional martial artist. He signed with the UFC and fought numerous times under their banner. However, fans never warmed to him and booed every appearance (via The Guardian). It was a major fall from grace for Hardy because he was making less money than his football days. The former Ole Miss star threw away opportunities and failed to reach his full potential.