Troy Aikman
Aikman served as the Cowboys’ starting quarterback throughout one of the franchise’s most successful eras. However, he suffered 10 brutal concussions with the team and arguably hung on for too long. This may have long-term health implications because of the damage he sustained.
Incredibly, Aikman wanted to play for the Dolphins before they refused to sign him. His final game saw LaVar Arrington smash him into unconsciousness in front of the world. Some players take irresponsible risks with their health and Aikman was one of them (via Sportscasting).