Phelps will swim the 100 and 400-metre freestyles -- as an underdog -- while giving up his most dominating events, the 400 individual medley and 200 butterfly.

"I'm going to switch gears and see what happens," Phelps told reporters Tuesday. "It's a good change. It will keep me interested and more in-tune to what's going on."

Phelps will swim in five individual events and three relays at the world championships, which began in Montreal this week. His coach, Bob Bowman, said it would be a "very tall order" for the Baltimore native to capture eight golds.

"I think it's a great opportunity to just kind of see where he is," said Bowman. "What kind of shape is he in? He's had an extended break, he had a back injury, he had some other issues, he moved to a new city.

"This is going to give us the first true picture of 'As of today, where does he stand in comparison to where he was a year ago?' And that's what we will find out next week."

Phelps, who won six golds and two bronze medals at the 2004 Athens Olympics [Images], appears to enjoy the underdog role. Australian Grant Hackett, for one, is expected to hit the wall before Phelps in the 400 freestyle.

HACKETT DOMINANT

"I like to race, I like to compete," said the 20-year-old Phelps. "The 400 is going to be a tough race. Hackett has been very, very dominant, very strong. It's my job to step up and try to race him. I'll try to go out after it and see what happens."

Australia's Ian Thorpe and the Netherlands' Pieter van den Hoogenband -- both of whom beat Phelps in Athens -- will sit out the championships.

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But Dave Salo, head coach of the U.S. Men's team, said Phelps' path to the podium will not be easy, especially in the freestyle events.

"Michael is very competitive," Salo said. "He wants the race. It would be real easy for him to take on the events he's expected to win. He's not afraid to lose. And that's a tribute to a champion."

Bowman said the world championships are the first step in a long road to the Olympics and a less-than-perfect performance in Montreal would be acceptable.

STEPPING STONE

"He's using this as a stepping stone for Beijing," Bowman said. "Quite frankly, after you've had a performance like he had in Athens, the only thing that will allow him to top that is the next Olympics. He can't really do that anywhere else."

The wholesome image of the affable 6-foot-4, 195-pound Phelps was tarnished last November when he was arrested in Maryland for driving under the influence of alcohol. The swimmer was sentenced to 18 months probation and fined $250.

Phelps, who now lives in Ann Arbor, Michigan, was contrite during his community service appearances. He knows how special his life is right now.

"The statement, 'The sky is the limit,' really is true," he said. "I never thought at the age of 20 I'd have eight Olympic medals that I'd be living a dream come true -- being a professional athlete doing something I love.

"This is my job. Growing up I always dreamt about this. It's all fun. I'm having a blast."