Now, it sounds like he's not so sure.
While saying he's never been happier with his life — and certainly doesn't miss the grind of what it took to become the most winningest athlete in Olympic history — Phelps left the door open to change his mind before the 2016 Rio Games.
"I don't know what's going to happen in the future," Phelps said Monday. "I don't know what's going to happen tomorrow."
In Barcelona for the world swimming championships, Phelps spoke to The Associated Press and other international media organizations in a series of one-on-one interviews set up by his sponsor, Speedo. When asked by the AP, yes or no, whether he'll compete at the next Olympics, Phelps coyly said he hasn't planned that far ahead in his life.
That's a striking change from his comments before and immediately after the London Games, when he insisted his retirement was set in stone and it had always been his goal to quit swimming before he turned 30.
Phelps will be 31 at the time of the opening ceremony for the Rio Games.
"I don't know. We're in 2013," he said, before adding, "There's nothing in the works right now."
There's plenty of time for a comeback. Phelps would likely want to begin training before the end of the year, which would allow him to get into peak condition leading up to the next world championships in 2015, an important stepping stone for the Olympics.
Phelps certainly isn't training at the moment. He jammed the small toe of his right foot on the edge of a sofa while at home in Baltimore, and aggravated the injury when he played in a golf tournament at Lake Tahoe.
He's wearing a boot cast on his foot while in Barcelona to cope with a small stress fracture.
After some sightseeing and promotional appearances, Phelps took in a second night of swimming at the Palau Sant Jordi before getting ready to head back to the U.S. on Tuesday. He was accompanied by his new girlfriend, Golf Channel reporter Win McMurry.
"I have no plans to do anything," Phelps said. "I love what I'm doing now. I'm able to travel so much, play golf. I'm on my schedule. I've never been able to have that. I've never been able to do really whatever I want to do. I go wherever I want to go. I see whatever I want to see. It's nice waking up at 10, 11, 12 o'clock in the afternoon. I'm pretty lazy besides playing golf. I don't do much."
He does have some projects away from the pool, including a series of swim schools and a foundation devoted to water safety. He said those are fulfilling projects, but he's still trying to sort out where he wants to go in his life.
"Peter (Carlisle, his agent) asked me where I want to be in one year, five years and 10 years," Phelps said. "I'm still in the process of putting everything down on paper."
While passionate about golf, Phelps seems to realize it doesn't present much of a career path other than playing in celebrity tournaments. He once talked bravely about not setting any limits on how far he could go in the sport, even joking that the only way he would be at the Rio Games was at a golfer (the sport is returning to the Olympic program in 2016).
But the game has clearly humbled him since London, despite getting lessons from famed coach Hank Haney as part of a show for the Golf Channel.
"I'm competitive in everything," Phelps said. "But golf has a very slow learning curve. For me to be able to get where I want to be, it's going to take some time to get there. It's not something that's going to take 24 hours and, bang, I'll be able to shoot par and be a scratch golfer. It's so annoying. It's probably the most humbling thing I've ever done, the most humbling sport I've ever done, the toughest thing I've ever done."
Phelps' competitive side showed after the U.S. men lost in the 400-meter freestyle relay on Sunday. The Americans were edged at the finish by the French, a repeat of last summer's Olympics when a team that included Phelps also settled for silver.
"We should never lose that relay with the talent we have on the team," he said.
While vague on a possible comeback, Phelps was downright candid with this thoughts about the relay — perhaps because the head coach of the U.S. men's team is Bob Bowman, who was Phelps' longtime coach and remains a good friend and business partner.
Phelps made his feelings known to Bowman in a series of blunt texts, suggesting the Americans should have gone with Jimmy Feigen in the leadoff spot and Olympic gold medalist Nathan Adrian as the anchor.
Instead, Adrian went first and Feigen took over for the finish despite being the least experienced member of the U.S. foursome. He acknowledged paying too much attention to the teams next to him, the Australians and the Russians, and not noticing the French coming up in an outside lane until it was too late.
"I was so fired up," Phelps said. "We have enough guys on that team who can swim faster than that, and that was just frustrating for me to watch."
Not frustrating enough to announce his comeback.
Not yet anyway.
That said, it's clear just about everyone on the U.S. team would love for Phelps to rejoin them in time for Rio. Though he always had to be treated a bit differently than everyone else because of his fame, he seemed to get along well with his fellow swimmers. He still stays in contact with many of them; in fact, he was hanging out with Allison Schmitt and Conor Dwyer at his home the day he hurt his toe.
Phelps has been catching up with the U.S. team during his quick trip to Barcelona.
"It was so good to see him. We miss him so much," said Missy Franklin, the star of the women's squad. "The team's not the same without him. But we still have an incredible team and he has taught us so much, and I think we're all excited to carry on his legacy after him."
The most experienced member of the team, Natalie Coughlin, said it was strange to be at a meet of this magnitude without Phelps.
"I haven't been on a team without Michael in 14 years, so this is pretty crazy," Coughlin said. "I would love to see Michael back. But I just want to see him be happy. He's enjoying his life right now and enjoying his time away from the pool and well deserved — very well deserved."
More Sports Headlines
Snohomish mixed martial artist returns to her first love Mariners beat Twins 4-3 in 11 innings Charles scores 29 points, Liberty beat Storm 78-62 Park wins Women's British Open, captures 4th different major Perry wins 2nd straight Champions Tour's 3M Championship Merritt shoots 67 to win Quicken Loans National by 3 shots Triple Crown winner American Pharoah wins $1.75 million Haskell Invitational Bills' Ryan names Incognito starting left guard
Our new comment system is not supported in IE 7. Please upgrade your browser here.