Some star athletes light up the sports world with their speed, strength or tenacity. They're incredible because they bring an edge to a game that had started to get boring. Unfortunately, if a good athlete is only that--a good athlete--he won't be remembered when it comes time to retire.

But then there are athletes who charm their way into our hearts. They make us laugh, cry, and, above all, root for them both on and off the court. When it comes time for these athletes to step down, they leave a hole in the game that can't be filled by the next biggest thing. To commemorate these athletes, our partners at Bleacher Report have shared a list of 20 athletes epic athletes that can't be replaced.

For more incredible sports stars, check out the 100 best athletes of 2012.