He is still just 28-years-old, but has not even played golf for fun in years and has now dropped out of the world's top 1000.But Kim is far from alone in having dropped like the proverbial stone after making a very promising start to his career.Here are other very notable bright young stars who simply fizzled out and disappeared without trace.US Ryder Cup star Anthony Kim burst onto the scene in the mid-2000s, won several tournaments and millions of dollars, became the sixth highest-ranked player in the world, and was the key player last time the US won the Ryder Cup.He is still just 28-years-old, but has not even played golf for fun in years and has now dropped out of the world's top 1000.But Kim is far from alone in having dropped like the proverbial stone after making a very promising start to his career.Here are other very notable bright young stars who simply fizzled out and disappeared without trace.Freddy Adu - footballerThe American former child prodigy, who shot to prominence 10 years ago when he became the youngest ever player to appear in a USA professional sport for DC United, was once dubbed "the next Pele". After horror spells in Portugal, France, Turkey and Brazil, he is now training as a free agent with, fittingly, a once-hyped club at Blackpool.Michelle Smith - swimmerBack in 1996, Ireland still did not have an Olympic-sized swimming pool, yet they boasted of the best swimmer in the world after Michelle Smith won three gold medals and a bronze at the Atlanta Olympics. Reportedly promised many sponsorship deals during the Games, Smith found they were not forthcoming after accusations of drug-taking were made against her. To this day, Smith refuses to talk about her swimming career and, despite never being stripped of her four Olympic medals, is rarely mentioned in conversations regarding Ireland's greatest sports stars.Jelena Dokic - tennis playerAfter reaching a career-high number four in the world rankings in 2002 and highlighted as a player likely to make a serious tilt at picking up a host of Grand Slam titles over the coming years, Dokic's fall from grace on and off the court was brutally swift. By 2005, at the age of just 21, she was in virtual retirement and estranged from her family while trying to rebuild her personal life. Problems with her incredibly volatile father Damir caught the headlines and her highly-promising tennis career was left in tatters.David Duval - golferThe American won The Open, became world number one (dislodging Tiger Woods) but then crashed out of the world's top 100 and could barely hit a ball. He very occasionally shows amazing flashes of what might have been, almost winning the US Open in 2009 but coming second, however it's just not what everyone had in mind earlier on.Ian Baker-Finch - golferThe once wildly popular Australian golfer once shot an incredible 66 to win The Open at Royal Birkdale. But after the highest of highs, he very famously lost his game almost completely - and in a desperate attempt to rediscover it, nearly lost his mind. After success in the world's biggest golf tournament came... well, nothing.Anna Kournikova - tennis playerThe Russian superstar made her professional debut at the age of just 14 in the Fed Cup for Russia, the youngest player ever to participate and win. She reached the semi-finals of Wimbledon in 1997, but then her sporting career took a dive. Her appearance and celebrity status made her a huge name worldwide but without a singles title to her name.Marcus Dupree - NFL playerIn 1981, college athletic recruiting changed forever as a dozen big-time football programs sat waiting for the decision by the physically powerful and lightning-quick high school running back Dupree. What sadly ensued, however, was a forgettable college career littered with conflict, injury and oversized expectations. The story has now become the focus of an ESPN documentary entitled, 'The best that never was'.Arturo Lupoli - footballer(uk.eurosport.yahoo.com)ANN.Az