Dara Torres, who won three silver medals at age 41 and just missed making her sixth Olympic team this year, tweeted that she's betting on a Phelps comeback.
"Anyone care to wager???" she wrote.
Phelps playfully tweeted back: "Yes I would love 2!!!"
"The competitive part of my career is over, but that doesn't mean I'm done with the sport," he said. "This sport has allowed me so many opportunities. I've had the privilege to do some of the coolest things in the world. I'm still going with my goal, to try to change the sport, to take it to a whole new level. It hasn't reached the peak that I want it to reach."
He plans to attend the world championships in Barcelona next year, and he's already promised his mom that he'll take her to the Rio Games in 2016. But before anyone gets the wrong idea, he quickly adds, "I'm not competing. I'm not competing. I'm not competing.
"I want to see what it's like being on the outside looking in," Phelps said. "It will be cool to see how people progress."
He's not at all worried about the U.S. program carrying on without him. Indeed, this was more of a team effort than the past two Olympics, which were dominated by Phelps' Herculean performances. He still won more medals than any other swimmer, but four golds and two silvers was a step down from Beijing. Even so, the Americans won 16 golds — their highest total in a non-boycotted Olympics since 1972.
Seventeen-year-old Missy Franklin captured four golds, equaling the U.S. mark for a female swimmer set by Amy Van Dyken in 1996. Allison Schmitt won three golds, plus a silver and a bronze. Fifteen-year-old Katie Ledecky nearly broke the world record in the 800 freestyle. And Ryan Lochte, who was a bit of a disappointment despite winning five medals, plans to keep on swimming.
"We have a great team right now," Phelps said.
One thing he doesn't want to do: Regain those 25 pounds he put on in 2009, when his enthusiasm for the sport waned and he wasn't even sure if he wanted to come back for another Olympics.
"I'm a person that's very goal-oriented," he said. "I'm sure I can find things to get excited and motivated for."
In keeping with the theme of a retrospective farewell, Phelps went with some slightly older hip-hop on his iPod during his eight days at the pool, songs he had used to fire himself up for previous meets and past Olympics.
When he walked on the deck for the final time Saturday night to take part in the 4x100-meter medley relay, he was jammin' to Young Jeezy's 2007 hit, "Go Getta," and a 2011 collaboration between Afrojack and Steve Aoki, "No Beef."
"I had those two songs kind of going back and forth," Phelps said. "Most of the meet, we threw in a couple of Lil Wayne songs. I kind of went old school. We didn't do too many new songs on this trip. We just put together everything I listened to over the years."
Phelps is eager to get home to Baltimore to be with his dogs, Herman and Stella.
Stella is a newcomer to the family, but she seems to be getting adjusted.
"I've been hearing stories and seeing pictures that Stella is more relaxed than before," Phelps said. "I want to be able to go home and hopefully not see Stella ripping Herman's wrinkles anymore. She kept doing that, and he would get so upset. But they like each other now. I definitely miss those guys. I remember the day I left, they all looked so sad."
He looked downright giddy about getting on with the rest of his life.
Follow Paul Newberry on Twitter at www.twitter.com/pnewberry1963