Michael Phelps happy to end retirement after two-year break

Michael Phelps speaks to the media after practice, Wednesday, April 23, 2014, in Mesa, Ariz. (AP / Matt York)

MESA, Ariz. -- Michael Phelps is making a comeback after nearly two years out of competitive swimming pool for the simplest of reasons: He missed the sport that has been his entire life.

The 22-time Olympic medallist tried golf and high-stakes poker in a quest to satisfy his competitive drives. He found nothing compared with pulling on a suit and diving in.

"Looking at a black line for hours on end, I don't know what made me do it," he said Wednesday, "but I'm having fun."

Having shed the weight he piled on since retiring after the 2012 London Olympics, Phelps will resume his career starting Thursday at the Arena Grand Prix. He will swim the 100-meter butterfly, an event in which he holds the world record. He dropped his plans to compete in the 100 freestyle the same day.

"I'm doing this because I want to," he told a gaggle of reporters and TV cameras gathered under a tent behind the pool. "Nobody is forcing me to do this or that."

Phelps insists he has few expectations beyond regaining his feel for racing, something he hasn't done since ending his career with a gold medal in the 400 medley relay in London.

"Just being able to get back into that mentality of competition, that's one thing I really loved the most about it when I was really competing in 2012 and throughout my career," he said.

The intense pressure that accompanied Phelps every time he stepped on the deck during the height of his career has dissipated. He appeared relaxed, smiling and joking with longtime coach and friend Bob Bowman at his side.

"Going into 2012 it was hard, there were a lot of ups and downs, and it was very challenging at times to get motivated," Phelps said.

Not this time.

Phelps resumed training last fall at North Baltimore Aquatic Club in his hometown, spurred on by a younger group of swimmers that includes Olympian Yannick Agnel of France. Phelps turns 29 in June.

"I really am the grandfather of the group, that's the worst part about it," he said.

Bowman and Phelps frequently clashed during his career, with Phelps rebelling against his coach's hardnosed style.

"He's much happier doing the training," Bowman said. "When he first came back he was so out of shape."

"Easy," Phelps scolded playfully. "Sugarcoat it at least."

The swimmer who owns a record 18 Olympic gold medals, including the eight he swept at the 2008 Beijing Games, returns without a suit sponsor and considers himself "a free agent."

Phelps isn't worried about marring the legacy he built over four Olympics.

"I'm doing this for me," he said. "If I don't become as successful as you all think I would be or should be and you think it tarnishes my career, then that's your own opinion. I'm doing this because I want to come back and I enjoy being in the pool and I enjoy being in the sport of swimming."

Phelps was noncommittal about whether his comeback would lead to swimming in the 2016 Rio Olympics, although he admitted that if he wants to compete at the highest level, he has to be ready by this summer.

"I am looking forward to wherever this road takes me," he said, "and I guess the journey will start tomorrow."