Barry Sanders was on the cusp of becoming the NFL's all-time leading rusher when he decided to walk away from the game in 1998.
It was Sanders' stunning exit from the game that provided the inspiration for this list.
Although the exact reason for his decision remains somewhat of a mystery, he has said he was simply tired of playing professional football.
Michael Jordan was tired of playing professional basketball when he walked away during his prime, choosing instead to pursue his dreams on the baseball diamond.
The actions of Sanders, Jordan and so many others has left us scratching our heads and wishing we could have seen more.
In some cases, athletes like His Airness have come back to deliver more spectacular moments.
In other cases, athletes like Sanders have stayed out of the spotlight for good.
Here's a look at 20 athletes who walked away too soon.