Swimming's new leading man was taking the plunge back into serious racing in the second round of the World Cup starting on Friday at the Melbourne Sports and Aquatic Centre.
The Baltimore teenager has entered five events for the three-day meeting as part of a long and exhausting process to prepare himself for next year's Athens Olympics.
In Athens, Phelps will try to emulate the greatest Olympic swimmer of them all, Mark Spitz, whose haul of seven gold medals at the 1972 Munich Games remains the benchmark of excellence.
Ian Thorpe, who won six gold medals at the 2001 world championships in Japan, is also eyeing Spitz's mark but his chances are rapidly sinking as Australia's relay teams slip further behind the United States.
Phelps swept past Thorpe as the world's top-ranked swimmer when he won four gold medals at this year's world championships in Barcelona, setting five individual world records.
He has reportedly been offered a $1 million bonus if he can win seven gold medals in Greece but the 18-year-old Phelps says he will be happy to win just one after coming away from the Sydney 2000 Olympics empty-handed.
"My goal right now is to come back with one and whatever happens after that happens," he told a news conference on Thursday.
WORLD RECORDS
"I went into this summer, the world championships, hoping for best times and I came out with all best times, five world records and four gold medals, so going in with an attitude like that things can happen."
Looking lean and relaxed after taking a break from competition following Barcelona, Phelps said this weekend's short-course meeting in Australia could provide the first clue to his chances next year.
"This is sort of a test to see where I am in training right now," he said. "I think I've had a pretty good year so far training-wise and hopefully we can turn it to the competition mode and hopefully pull out some good times."
While Phelps has established himself as the world's best in medley swimming and 200 metres butterfly, the lure of chasing seven gold medals might force him into uncharted waters.
That could mean challenging Thorpe over 400 metres freestyle, where the Australian is considered virtually unbeatable.
Phelps was hoping to test himself against Thorpe during the World Cup but will have to wait for another chance because the Australian is busy working on his sprints as part of his plans to win the 100-200-400 freestyle treble.
"It would have been fun to race one of the world's top swimmers but there's a time and a place for everything," Phelps said.
"I guess it didn't work into both of our schedules that we planned."