By Brian A. Shactman
CNBC.com

Michael Phelps is as close to a living Olympic legend as you can get. He's won 16 Olympic medals, including eight golds in the 2008 Beijing Games.

As he enters the London Games, yet again, there are high expectations. With three medals, Phelps would become the top medal winner in Olympic history.

It's difficult to imagine that not happening, and either way, his athletic legacy seems secure.

But what about his brand and earning power?

With the emergence of fellow American Ryan Lochte, it's possible that Michael Phelps isn't a runaway success in London. There, I said it.

"If he walks away with no medal at all, it would be a tremendous disappointment and devastating for the brand," said brand expert Laura Ries. "People want winners, especially Americans."

With so much attention focused on Phelps and his records, there is potential for disappointment, even if that scenario seems unlikely.

"The signs are good," Ries said. "Michael Phelps has been at this a long time. He's very seasoned and has been avoiding the press and handles the pressure well. But what happens in the pool is unpredictable."

Some estimates are that Phelps' long-term earning power could be upward of $100 million. Right now, sponsors include Speedo, Hilton, Subway, Visa, Proctor & Gamble, HP, Topps and Omega.

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For a sport that's prominent in the nation's consciousness once every four years, that's a lot.

On the corporate side, most of the deals are long term and couldn't be substantially changed even if Phelps performed poorly. So, most sponsors are with Phelps, for better or worse.

"Phelps is a proven commodity with a great brand," said Rob Prazmark from "21 Marketing", who has been involved with more than a dozen Olympiads, several from the corporate marketing side. "If he does not do well, his brand will continue to stay strong. He already has a track record and has accomplished so much. Yes, there are expectations but not like Beijing."

A lot of the near-term fate of the Phelps brand depends on Ryan Lochte. Many will simply respond with: Who?

Well, he isn't quite the household name like Phelps, but in 2012, Lochte just might be a better swimmer. What's more, marketers have been scrambling to make sure that, if Lochte is a break-out star, he's poised for the exposure ... and the money.

Lochte has been a major coverboy this spring/summer, donning the front of magazines like Men's Journal and Vogue.

"Lochte could walk away the bigger star," Ries said.

At this point, Lochte has contracts with Gatorade, Ralph Lauren, Gillette, Mutual of Omaha and Speedo. Reportedly, if he wins enough, it could translate into more than $3 million. Not bad for a super-talented athlete his coach characterized as having an "airhead quality" in a recent Sports Illustrated feature.

Within the swimming community, there's a chance Lochte has a huge Olympics.

Interestingly, if that happens, it could actually help Lochte and Phelps. Because of Phelps' medal count, he's already in rarified air. If he loses races by a lot, it won't be good, but if he loses close races to Lochte, the coverage and competition could actually enhance the Phelps brand.

"People love the rivalry," Ries said. "If it's a 1-2 finish, that might end up just as good as gold."

Regardless of the outcome, the London Games will be hard-pressed to find a storyline better than Phelps vs. Lochte and whether Phelps will be able to endorse products for the rest of his life.

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