23. Rob Gronkowski
When a player unretires they should ask themselves why they retired in the first place. ‘Gronk’ is an NFL legend, and even fans who hate the Patriots can’t dislike him. After returning to football, the Super Bowl winner joined the Tampa Bay Buccaneers where he has run hot and cold alongside Tom Brady. However, this isn’t just about his deteriorating influence on the field, but also the effect on his body.

Gronkowski is one of the smartest players in the league when it comes to money. He doesn’t need anymore, because he effectively saved all of his salaries and lived off of sponsorships. However, during his career, he suffered at least 20 concussions including five blackouts. In sum, he doesn’t need to play anymore and is risking his long-term health to do so. A long NFL career can destroy a man.