Aaron Boone sent the Yankees to their most recent World Series with an 11th inning home run in game seven of the 2003 ALCS against Boston's Tim Wakefield. Since then, he's bounced around and landed with the Astros for 2009. Boone underwent open-heart surgery in March to replace a bicuspid aortic valve and was unsure if he'd play baseball again. On Wednesday, Boone made his return to the big leagues and went 0-for-3 while playing first base for the Astros.
Many injuries in sports are relatively easy to recover from. Often, surgeries don't end a player's season or career. Open heart surgery is a much different operation than most athletes ever have to endure during their careers. I can't think of another athlete that ever had such a serious operation and returned to action that same year.