Michael Phelps is playing down expectations about his return to competitive swimming but the most decorated Olympian of all time, with a mind-boggling 18 gold medals, is finding it tough to sell himself as an underdog.

On Wednesday, the 28-year-old fronted a packed media conference on the eve of his eagerly awaited comeback at a US swimming Grand Prix meet in Mesa, Arizona.

He arrived unshaven, a little plumper than normal and with no swimsuit sponsor, and with the news that he had already pulled out of Thursday's 100 metres freestyle heats to concentrate on the 100m butterfly and Friday's 50m freestyle.

If I don't become as successful as you all think I would be or should be, and you think this tarnishes my career, then that's your own opinion

Michael Phelps,

"I haven't signed any contracts, no one's making me do this. I'm doing this because I want to," he explained.

"I'm loving just being back in the water and in a group. I'm even more relaxed than I ever was before. I'm smiling a lot, I'm happier, I'm joking a lot. I really am the grandfather of your group now. I'm the old man."

Rio hopes

While Phelps evaded questions about his chances of winning more gold in Rio, he did break away from his mantra that he is just doing it all for fun. Rio is still more than two years away but the timing of his return to competition this week is the first real clue that he has his heart set on adding to his golden stockpile in Brazil.

The history of sport is full of failed comebacks but Phelps, who will be 31 by the time Rio rolls around, said he was unfazed by what people think about his return if he failed to live up to his previous standards.

"I'm doing this for me. If I don't become as successful as you all think I would be or should be, and you think this tarnishes my career, then that's your own opinion."

Source: Reuters