MESA, Ariz. — Michael Phelps ended the first meet of his comeback on an odd note Friday, using his butterfly stroke to swim a 50-meter freestyle race that's never been part of his repertoire.
He was swimming to tinker with his form, not to win. And the race proved a side note to a week with greater implications for the record-setting Olympian and the sport he has loved since childhood.
Phelps' return sent a charge through what would have been a routine meet, and the shock waves will continue to ripple through the swimming world as long as he's around.
For the sport, Phelps is a signature star, capable of producing ticket sales, media attention and Olympic hype like no other.
For him, the comeback is both a source of joy and a potential marketing boon worth millions of additional dollars.
For swimming's rising talents, Phelps is like a living myth, a previously abstract standard of excellence who might now actually jump in the pool with them.
For old rivals, he's inspiration to get the competitive juices flowing for a few more years.
If Mesa is any evidence, world-class swimming is simply a more interesting neighborhood with Phelps in residence. And the path from here to the 2016 Olympics in Rio de Janeiro suddenly seems more exciting for everyone involved.
"Conventional wisdom would have had the road to Rio starting a year out, maybe 100 days," said Matt Farrell, chief marketing director for USA Swimming. "But his performance has just completely changed the definition and made it a different ballgame. He's the single most qualified person to make that happen."
Farrell said Phelps transcends the sport as an endorser of nonswimming companies such as Subway and Under Armour. His power on that front will only grow if he continues to swim at a high level.
The most interesting news might flow from the end of Phelps' career-long relationship with Speedo, the traditional 800-pound gorilla of competition swimwear.
"It's like imagining Tiger Woods outside of Nike," Farrell said.
He added that if Phelps signs with one of Speedo's competitors such as Arena or Tyr, it would be "an absolute game changer."
Could Under Armour, which already has a four-year relationship with Phelps, take this opportunity to dive into the swim market with him as the face of the initiative?
"That's a very interesting question," Farrell said. "It's not very common to see a new player come in and go to the highest level of the sport like that."
Phelps has only said he's a "free agent" in the swimwear market. But he didn't dismiss the Under Armour idea Friday and praised the company's CEO, Kevin Plank.
An Under Armour spokeswoman did not reply to a request for comment.
As much as he seemed to bask in the atmosphere he'd created, Phelps was the one person who didn't speak with certainty about his ongoing comeback. At least publicly, he continues to portray it as an open-ended exercise, one that will persist only as long as he's enjoying himself.
"It's one meet," he said when asked about Mesa's impact on his future thinking. "It's a long way, whether I decide to continue or not. This was awesome. I'm really excited about how things went. And I know what I need to do if I want to continue and want to swim faster."
When pressed further about his plans, he didn't budge from his conditional tone.
"I'm not saying yes or no yet," he said. "I'm doing this because I want to, and I'm doing it because I'm having fun. I'm not putting any pressure on myself to say I'm doing this or say I'm doing that in the future. I'm just enjoying myself right now and this road and this process, this journey."
It's not clear what's next for Phelps. His longtime coach, Bob Bowman, indicated he might swim another short program May 15-18 at the Charlotte Grand Prix. His performance in Mesa qualified him to swim at the U.S. Nationals in August, but he hasn't committed to that meet.
Neither swimmer nor coach was thrilled with Thursday night's 100-meter butterfly final. Phelps used the butterfly in Friday's 50-meter freestyle in part because he's still seeking his old rhythm.
But even a detail maven such as Bowman was able to step back and appreciate the greater experience of Phelps' return.
"It's fun to have him here," he said. "… I just think having him back in the sport is great. As long as he's enjoying it like he is, it's good for everybody."
Phelps can hardly escape reminders of his influence on younger swimmers. He's the self-professed grandpa of the star-studded team at North Baltimore Aquatic Club. In Mesa, he met 15-year-old phenom Michael Andrew, regarded by many as the eventual heir to Phelps' throne.
Andrew, a Kansas native, fired off several star-struck tweets about the encounter. "Swimming needs you!" he said in one. "So excited to race the GOAT [greatest of all time] this week!!!" he enthused in another.
Andrew didn't swim a fast enough qualifying time to set up a meeting with Phelps in the 100-meter butterfly. But he watched from the deck as his idol returned to competition.
Justin Lynch, 17, did get to swim against Phelps in the butterfly final. "It's a whole other level racing against the best in the world," he said.
Yet no one seemed more excited about Phelps' return than his old rival, Ryan Lochte, who won their Thursday duel in the 100-meter butterfly.
"I probably wouldn't have gone that time if Phelps wasn't in that pool with me," Lochte said. "Racing against him is so much fun. It's a challenge. And now that he's back, I've got a big, old smile on my face."
Lochte spoke with uncommon emotion of renewing his competitive friendship with Phelps, whom he hadn't seen since the London Olympics. He even said his rival's retirement "broke my heart a little."
Asked his reaction to Lochte's comments, Phelps seemed a bit taken aback. Perhaps he's still getting used to the impact of his return, even if he's always held ambitions to change his sport.
"I've said this my whole career and I'll continue to say it: This sport has given me so much and I don't think I can do enough to give back," he said. "This has been an amazing journey I've gone on so far, and I just hope it continues."