The most decorated Olympian of all time is taking a hiatus from competitive swimming after being arrested for a second DUI last week.
"The past few days have been extremely difficult," Phelps tweeted. "I recognize that this is not my first lapse in judgment, and I am extremely disappointed with myself."
I'm going to take some time away to attend a program that will provide the help I need to better understand myself.
- Michael Phelps (@MichaelPhelps) October 5, 2014
He then added: "Swimming is a major part of my life, but right now I need to focus my attention on me as an individual, and do the necessary work to learn from this experience and make better decisions in the future."
The 29-year-old swimmer is in the middle of a comeback after retiring at the 2012 Olympics. He has won a total of 22 medals, including 18 gold medals.
On September 30, Phelps announced that he had been "arrested and charged with DUI, excessive speeding and crossing double lane lines. ... I understand the severity of my actions and take full responsibility."
Police said in a statement that Phelps was driving 84 mph in a 45 mph zone when he was pulled over. If convicted, he faces up to one year in jail, a $1,000 fine, and the loss of his driver's license for six months.
Phelps was arrested for DUI in 2004 and received 18 months probation.
Tony Manfred contributed to this report.