One of these things is not like the others

Today is Labor Day, so let's celebrate some successful young athletes!

Serena Williams. Turned pro at the age of 13. By the time she was 19 she had won seven WTA events.

Bryce Harper. Left high school after his sophomore year, and enrolled at the College of Western Nevada. Drafted No. 1 overall in the 2010 draft, and signed a 7-year, $18.9 million contract with the Washington Nationals.

Zach Bogosian. From the Cushing Academy in Massachusetts, Bogosian was drafted third overall in the 2008 NHL Draft at the age of 17. His current contract is valued at $5 million for two years.

Freddy Adu. Drafted when he was 14, Adu appeared professionally in his first soccer game that same year. He's been playing professionally ever since.

Michell Wie. Abandoned her amateur status when she was 15 to become a professional golfer. In doing so she instantly became a multi-millionaire by signing endorsement contracts with Nike and Sony which were valued at over $10 million a year.

Shabazz Muhammad. 18-year-old freshman at UCLA. Unable to play in the NBA even though he would have been a top-5 draft pick in the 2012 NBA Draft, and would have signed a contact worth several million dollars. May be ineligible to ever play college basketball, as the NCAA has been investigating for several weeks whether someone who isn't one of his parents paid for him to visit a college campus during his recruitment.