Jay Williams
Jay Williams was supposed to be one of the cornerstones in which the post-Michael Jordan era Chicago Bulls were to be rebuilt upon. After one of the most decorated college careers in the history of the NCAA, the Bulls selected Williams with the #2 overall pick in the 2002 NBA Draft. After completing a promising rookie season, which saw Williams record the first triple-double by a Bulls player since Jordan himself, Williams was involved in a self-inflicted motorcycle accident, when he crashed his Yamaha R6 motorcycle into a streetlight.
Williams injuries included a severed main nerve in his leg, fractured pelvis and three dislocated ligaments. The damage was so bad that he required physical therapy just to regain the use of his leg. Those injuries instantly stripped him of the athletic ability he showed while at Duke University, or during his rookie season. He never again played in a meaningful NBA game.