The 2012 Olympic Games begin two years from today, and nearly every major star from Beijing has left the door open for a return in London, including swimmer Michael Phelps and sprinter Usain Bolt. Here's an update on 10 of the biggest names eyeing the London Games:

London could be the farewell for the second-most decorated Olympian ever (Soviet gymnast Larisa Latynina won 18 medals from 1956 to '64; Phelps sits with 16). Phelps said he'll reduce his London schedule compared to 2004 and 2008, when he entered eight events each.

Since we left him in Beijing, Phelps forayed into freestyle sprints, tinkering with and then shelving a windmill stroke. His surest bets for gold are the 100- and 200-meter butterfly (winning both at the '09 world championships with world records among his five golds) and in the three relays. Next up is August's national championships in Irvine, Calif.

Bolt has since surpassed Phelps as the world's most exciting Olympian. He lowered his 100- and 200-meter world records at the 2009 world championships in Berlin.

Like Phelps, Bolt considered a change in his program, pondering running the 400 for the 2010 season, a year that does not include a world championship. While a serious run at the 400 hasn't come yet, Bolt continues to dominate the 100 and 200. He's undefeated in both distances the last two years while rivals Tyson Gay and Asafa Powell continue to give futile chase. Expect Bolt to amp up his training and challenge his world records beginning at the 2011 world championships.

Nobody has come back for a second Olympic gymnastics team since 2000, but 2008 all-around silver medalist Johnson and gold medalist Nastia Liukin are working back into shape in case they opt to give it a shot.

Johnson officially announced a comeback; Liukin remains undecided. As for the possibility of competing in London, Johnson is more likely because she's younger by two years and has unfinished all-around business. Still, it's a tall task to overcome 2008 teammate Bridget Sloan and fellow American Rebecca Bross, who went 1-2 at the 2009 world championships. Remember, only two athletes per nation may compete in the all-around.

If anybody is going to be within sight of Bolt in London, count on Gay. The same was said leading up to Beijing until Gay suffered a severe hamstring injury at the Olympic trials. Unfit, he didn't reach the final in the Olympic 100.

Gay rebounded at the 2009 world championships, running the third fastest 100 time ever. Unfortunately, Bolt bettered his world record and won by an easy 13 hundredths. This year has been relaxed for both, but they are scheduled to be on the same track for the first (and perhaps only) time Aug. 27 in Brussels. At that 100-meter race, we'll get an updated measure of the true distance between Bolt and Gay.

For as in sync as they were in winning gold in 2004 and 2008, May-Treanor and Walsh have been unsettled since. May-Treanor tore an Achilles tendon while on Dancing with the Stars shortly after the Beijing Games, but she's back in the sand now. Retirement has been on her mind so she can spend more time on the road with husband and Texas Rangers catcher Matt Treanor. Meanwhile, Walsh had her second baby, leaving May-Treanor to play with a substitute partner this season, Nicole Branagh.

Age and the uncertain future of the AVP beach volleyball tour are potential hazards. May-Treanor will be 35 come London. Walsh will be 33.

Olympic gold medalist comebacks came in threes this year. Shawn Johnson and Laura Wilkinson announced returns, and Hamm followed suit last week. He released a video to prove he's for real. The 2004 Olympic all-around champ (he was injured for Beijing) is figuring out where he wants to live and train and wants to begin competing again in 2011.

With a fit Hamm and anchor Jonathan Horton, the U.S. men could contend for their first team gold in a fully attended Games. That would be a sweet sendoff.

Barring a Dara Torres Olympic appearance at age 45 -- which isn't out of possibility -- Coughlin should again grab the swimming headline leftovers from Phelps. An 11-time Olympic medalist, Coughlin needs two more medals to break Torres' record for most in a career by a U.S. woman. She took an 18-month break after Beijing, just recently returning to major competition.

She promptly won her signature event, the 100 backstroke, in her comeback meet in March and again at the Los Angeles Grand Prix two weeks ago. Coughlin added an event she hasn't raced in three years -- the 50 freestyle, which is Torres' pride and joy. Coughlin will compete at nationals with Phelps and Co. Torres will not. She's still recovering from October knee surgery.

Though Felix won the last three world titles in the 200, she's only won silvers at the Olympics. Jamaican rival Veronica Campbell-Brown swooped in for Olympic gold in 2004 and 2008.

Felix seemed to be forging ahead after Beijing, but Campbell-Brown again nipped her at the adidas Grand Prix last month in their only head-to-head meeting on the 2010 Diamond League circuit. But all is not lost. Felix won two major 400-meter races this year and the U.S. championship in the 100, keeping her options open for a variety of sprints and relays come 2012.

Jeter (pronounced like the airplane, not the Yankees shortstop) has been a sprinting force since missing the 2008 Olympic team. She flew to No. 1 in the world in the 100 with six wins in seven major races this season. She's also raising eyebrows by peaking sharply at age 30 after mostly pedestrian results in her 20s.

Jeter ran a season's best 10.82 in her most recent victory last week in Monaco. Contrast that with previous U.S. 100-meter dynamo Lauryn Williams, who hasn't broken 11.40 this year and ran 12.14 in early July, albeit into a massive headwind. It's shaping up to be Jeter versus Jamaica in 2011 and beyond.

The U.S. hopes to win its first diving medal in London since 2000, and Wilkinson may own similar plans. Wilkinson, the 2000 Olympic platform gold medalist, quietly came out of retirement and qualified for the national championships on the springboard. That meet comes in August.

Wilkinson says she is not coming back for competitive reasons. Rather, the 32-year-old wants to enjoy the summer and see where it leads. With or without Wilkinson, USA Diving could finally regain the podium in London. Americans won four medals at the 2009 world championships.

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.