HIV diagnosis in 1991. Retired immediately. The world thought he was going to die. He didn't — he came back briefly in 1996. But we lost 5+ prime years of the most entertaining player ever.
Won MVP at 25. Then his feet broke. Literally. Played only 468 career games. When healthy, he was the most skilled center ever. He was almost never healthy.
Was "the next Jordan" in the mid-90s. Ankle injuries robbed him of his prime. He reinvented himself as a role player in Phoenix, but the first version of Grant Hill was Hall of Fame level.
At 21, he was the best center in basketball. Averaged 18/12. Then his knees disintegrated. Tried bowling instead of rehab. Never played another NBA game. The weirdest career arc in NBA history.
Rookie of the Year. 3x All-Star. His knees had no cartilage left. That Game 4 comeback against Dallas in 2011 — 18 points in the 4th quarter on one good knee — was his last great moment. Retired the next year.