Phelps, 28, has not competed since the 2012 London Olympics, where he won four gold and six total medals, giving him Olympic career records for both (18 and 22.)
Phelps' coach, Bob Bowman, told the Chicago Tribune on March 25 the swimmer would probably get into a meet "sometime soon."
USA Swimming announced Monday that Phelps was expected to compete in Mesa. Phelps intends to swim the 50- and 100-meter freestyles and 100 butterfly, according to his agent, Drew Johnson of Octagon.
The swimming community welcomed the news.
"Michael is the greatest swimmer of all time. His return to competition will drive excitement and interest not only for fans and media but also his fellow swimmers," Conor Dwyer, who trains with Phelps in Baltimore and swam with him on the winning 4 x 200 free relay in London, said in a text message.
"He brings a level of excitement and recognition that no one else can," Cordes said.
Bowman had told the Tribune it was "too early to tell" whether Phelps would try to earn a place on the U.S. team for the 2015 world championships. The 2014 U.S. championships this August in Irvine are the selection meet for the 2015 world team.
"If he swims a meet in the next couple months and does well, he will probably give it a shot in Irvine," Bowman said. "But he doesn't have to do that to have a shot at the 2016 Olympics."
Bowman had said Phelps probably would concentrate on relays and shorter events, including the 100 freestyle and 100 butterfly. He has won individual event Olympic gold medals in the 100 and 200 butterfly, 200 and 400 individual medley and 200 freestyle.
"This season, I'd guess he'll jump right back on top of the world rankings," Grevers said. "Since it's still a tuneup season, I don't think we should expect any new world records."
Backstroker Grevers spoke with pride in London of having led off the victorious medley relay that was billed as Phelps' final race.
"He is my swimming idol," Grevers said.
Quadruple Olympic gold medalist Janet Evans, a three-time Olympian, wrote in a text message that Phelps' return will lead other swimmers to feel that way.
"It is great for our sport, of course," she said. "Another generation of athletes for him to inspire and influence and a lot of attention to the sport heading into Rio."