Phelps began his comeback last month at the Arena Grand Prix in Mesa, Ariz., where he finished second in the 100-meter butterfly to longtime rival Ryan Lochte, who is also expected to swim in Charlotte.
Fun was Phelps' favorite word in Arizona, where he talked about how happy he was to be back in the pool after a 20-month retirement. He refused to commit to any long-term plans, including the 2016 Olympics in Rio de Janeiro.
But the record-setting Olympian's presence created a festive atmosphere at the Mesa meet, where tickets sold out rapidly as soon as Phelps confirmed he'd swim.
After Phelps competed in the butterfly and the 50-meter freestyle (he used a butterfly stroke and failed to qualify for the final), longtime coach Bob Bowman said he might swim a similarly short program in Charlotte. The meet could allow him to post qualifying times in more events, as he moves toward a possible appearance at U.S. Nationals in August.
Bowman told the Associated Press Phelps is entered in the 100-meter butterfly and 200-meter freestyle in Charlotte, both scheduled for May 16. In Arizona, he withdrew from the 100-meter freestyle, because he didn't want to compete in two events on the same day.
Phelps hasn't committed to U.S. Nationals, which will in turn determine the make-up of the U.S. team for World Championships next year. But he did indicate in Arizona that he'd have to be in top shape by this summer if he was serious about swimming at a world-class level in the run-up to Rio.
"This was awesome," Phelps said after the meet. "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."