Another medical/sports post? What body part would you sacrifice to improve your sports performance?

Here's another little medically related sports tidbit... or sports related medical tidbit. Hey, what else am I going to write about? You guys are far more versed in sports than I.

Anywhom, NPR had a piece today about R. A. Dickey, a pitcher in the Seattle Mariners' organization who lacks an ulnar collateral ligament (you might also find other stories by Googling "ulnar ligament knuckleball") but keeps chugging on. In essence, Dickey has developed a knuckleball to prolong his career in spite of the congenital abnormality that should render his arm somewhat incapable of pitching.

I was only half-listening to the piece and initially thought the story was about how this strange deformity actually made the pitcher capable of throwing really bizarre pitches. However, upon researching Dickey further, I realize that the ulnar collateral ligament deficiency does not at all make him a better knuckleballer.

Nonetheless, I briefly entertained the thought of what other physical abnormalities would confer a competitive advantage to athletes. The best deformity I could think of was a center in basketball who's wrist could flex in both directions, thereby giving said center the greatest hook shot ever.

Any one have any other ideas? We're talking about conditions that might be considered deformities in the real world, not bogus superhuman capabilities or fictional injuries that enhance a player's abilities.