There were those 18 Olympic gold medals for his career, 13 of them individual, and a total of 39 world records — three of which he still holds in individual races.
Most of all, Phelps took with him the title of the most-decorated Olympian of all time. That's something you just don't replace.
USA Swimming, however, is looking for a new poster boy. Actually, given the fact Phelps left his mark in 11 events, there are many 'new' faces that need to fill the considerable void left by the world's greatest swimmer.
Phelps' best event was the 200-meter butterfly. He was pretty good in the 100 fly, as well. Those are two big reasons why Stanford graduate Bobby Bollier will be competing at the Phillips 66 National Championships next week in Indianapolis, Ind., instead of being retired as well.
"It's my events Michael Phelps is leaving behind," Bollier said this week. "U.S. Swimming is looking for fast people to fill that in."
Bollier, for one, is a bit relieved that Phelps is no longer taking one of two berths for every major swim meet.
"It's not like he was a distraction," Bollier said. "If anything, he was a motivating factor. But, his departure provides opportunities for people like me."
Bollier is scheduled to swim the 200 fly, 200 free, 100 fly and 400 free at the national championships, which serves as the qualifying meet for the FINA World Championships July 28-Aug. 4 in Barcelona, Spain. Only the top two finishers in each event are eligible for the USA team.
Bollier knows the pain of not finishing among the top two after taking third at last year's U.S. Olympic Trials. He went into the final having clocked the fastest times in the prelims and semifinals, but his personal record of 1:55.79 in the finals left him behind Phelps and Tyler Clary.
"I put everything into that race," Bollier said. "I have no regrets. Even though it would have been awesome to make the team, I got everything out of it that I could — even though I didn't get the icing on the cake.
"Trials were a huge mix of ups and downs. Short term, I'd say it was definitely a negative simply because I didn't make the Olympic team. When you get third at Olympic Trials, it's really humbling. But, long term, it's just something else that happened in the past. I learned a lot about what's important to me, what defines a swimming career, and what makes the whole swimming experience so enjoyable."
Following the Trials, Bollier took nearly two months off from swimming. But, because his family had tickets to the London Olympics, Bollier made the trip with them,
"I went to London to see some events and got to explore the city, something I wouldn't have done has I made the team," Bollier explained. "It was an alternate Olympic experience and a good way to get closure on not making the Olympic team — just seeing there were other ways to enjoy the Olympics without competing in it."
Bollier met up with Shannon Vreeland, a former teammate of his with the Kansas City Blazers' club. She earned a gold medal on the 800 free relay team. They had lunch together after her relay win.
"I had a lot of friends on that (Olympic) team," said Bollier.
Fortunately for Bollier, he had made a fortuitous decision back in March of 2012 that he'd swim at least through 2013.
"I made the decision in advance because I didn't want the Olympic Trials to be the deciding factor on my career," he said. "I was very happy with that decision, It took a lot of pressure off me at Olympic Trials."
The 23-year-old Bollier, who graduated from Stanford last June, eventually got back to training in September of 2012 and rejoined a small group of his former teammates with Stanford Pro Elite. The post-grad team trains with Palo Alto Stanford Aquatics with Tony Batis and at Stanford with head coach Ted Knapp and assistant Scott Armstrong, who ironically used to help coach Phelps at the North Baltimore Swim Club.
Bollier's teammates include Eugene Godsoe, Chad La Tourette, Jason Dunford, Geoff Cheah, and B.J. Johnson. Godsoe, La Tourette and Johnson will be swimming at nationals next week, as well.
Bollier is seeded No. 2 in the 200 fly, La Tourette is No. 2 in the 800 free and No. 3 in the 1,500 free, Johnson is No. 3 in the 200 breast, and Godsoe is No. 3 in the 50 and 100 backstrokes plus No. 5 in the 50 and 100 flys.
Bollier said he's "optimistic" about his chances next week.
"I've had a good year," he said. "I'm in good shape right now . . . The swimming perspective is interesting, as well."
Along with training with his friends and high school swimmers with PASA, Bollier served as an assistant swim coach at Menlo-Atherton High this past season under former Stanford All-American Lori (Heisick) Stenstrom. She shares a special bond with Bollier — she finished third in the women's 100 breast at the Olympic Trials in 1988.
"My experiences have definitely given me a renewed attitude about the sport," said Bollier, "and I'm excited for the rest of 2013 and beyond."
The Phillips 66 National Championships should be a good one, with many of the 2012 U.S. Olympians returning to re-establish themselves while many up-and-comers are looking to make a splash.
The top PASA entrants include Palo Alto High grad Jasmine Tosky (No. 4 seed in 200 fly), Sacred Heart Prep's Ally Howe, Curtis Ogren of Menlo Park, Gunn grad Rachael Acker and Paly senior Andrew Liang.
The Stanford men will be led by junior David Nolan while the Cardinal women have Maya DiRado and Felicia Lee, among others. Palo Alto High grad Liv Jensen (50 free) and Stanford grad Randall Bal also will be among the talented fields that include more than 30 members of the 2012 U.S. Olympic team.
The meet runs Tuesday through Saturday at the Indiana University Natatorium.