Can you guess who these professional athletes are?

Many professional athletes started playing the sports they found careers in at a young age -- but we don't often see them from their little league or youth basketball days. Athletes like Derek Jeter and Tom Brady dabbled in other sports before finding their true callings. Some were labeled prodigies of their craft at ages when many other kids were still getting the hang of walking. There are also athletes who followed in their parents' footsteps.

Click through the gallery below to put your sports knowledge to the test with throwback pictures of some of the top names in sports -- because who doesn't love a little friendly competition?