Athletes such as Jordan and Woods did not become marketing titans by appearing in as many commercials as possible. They forged lasting relationships with a few heavyweights that built creative campaigns around them.

Though Phelps has worked with Speedo for years and is happy with the relationship, Carlisle says to expect major sports apparel companies to come calling. Nike seemed to signal that it was out of the Phelps sweepstakes when the company announced recently that it would no longer focus on developing high-end swimwear. But when asked whether shoe companies have made plays for Phelps, Carlisle said, "I would imagine most sportswear companies have some interest in working for Michael."

Beyond traditional endorsement deals, Phelps could be a hot commodity in the ever-expanding world of reality television. Though Carlisle wouldn't discuss specific ideas, he said he keeps a Phelps-related file on his computer titled "weird offers."

He isn't sure about Phelps the television star. "He's not going to do something for the sole reason of getting publicity," Carlisle said.

The swimmer echoed that sentiment when asked about television, saying: "I have no idea. I don't know. I'm just going from town to town right now. I really haven't thought too much about anything."

Phelps was thrilled, however, to see that the interest in Olympic swimming prompted NBC to add events such as the FINA world championships to its broadcast plans. Carlisle said he could imagine those plans expanding to a series of match races.

"The personalities could really come into play," Carlisle said. "I'd love to see something like that. You've got to change the packaging somehow, to give people access they don't normally get so it feels relevant beyond the Olympics. That could bring it more in line with the way people are interested in other sports."

Carlisle said such a tour is a wish more than a tangible plan because Phelps isn't even thinking about competing for the time being.

Whenever Phelps does get back to it, the North Baltimore Aquatic Club and its home off Falls Road will be the base for his efforts. Phelps trained at the club until 2004, and Bowman has taken over as CEO. Whether Phelps will buy the Meadowbrook facility where NBAC operates - as he indicated at the Olympics that he might - remains uncertain. But he will be the chief public face of a club that began its Olympic legacy before he ever dipped in the pool.

"Any involvement he can have there, that can be a great platform for him to discuss all these things he's interested in," Carlisle said.

Baltimore Sun reporter Kevin Van Valkenburg contributed to this article.