The sport's national governing body also cut off its financial support to Phelps for the same three-month period, effective Thursday.
"This is not a situation where any anti-doping rule was violated, but we decided to send a strong message to Michael because he disappointed so many people, particularly the hundreds of thousands of USA Swimming member kids who look up to him as a role model and a hero," the Colorado-based federation said in a statement. "Michael has voluntarily accepted this reprimand and has committed to earn back our trust."
Phelps won a record eight gold medals in Beijing and returned to America as one of the world's most acclaimed athletes. Now he's enduring a wave of bad news in the wake of the photo, published Sunday by News of the World, a British tabloid.
Earlier Thursday, cereal and snack maker Kellogg Company announced it wouldn't renew its sponsorship contract with Phelps, saying his behavior is "not consistent with the image of Kellogg." The swimmer appeared on the company's cereal boxes after his Olympic triumph.
Phelps has acknowledged "regrettable" behavior and "bad judgment." He didn't dispute the authenticity of the photo, reportedly taken at a house party while Phelps was visiting Columbia, South Carolina, in November during an extended break from training.
The 23-year-old has resumed training in his hometown of Baltimore, but his plans to return to competitive swimming will have to be put on hold. Phelps had been planning to compete in early March at a Grand Prix meet in Austin, Texas.
Now, he won't be able to allowed to compete until early May, which would give him just over two months to get in some racing before July's world championships in Rome.
Phelps caught up with Kevin Van Valkenburgh of the Baltimore Sun for an exclusive interview.
What did the experience remind him...?
"There are always people you can't trust," he said. "During the whole thing, I've really been able to see who my friends are, who my family are, and who really loves and supports me. They've stood by my side, from the countless text messages, phone messages, e-mails, those are your friends. All those people who are around during the good times? Those aren't your friends."
Those of us here at OSG HQ remind the young man that his count is now 0-2...
Don't get caught looking at the next pitch...