USA Swimming suspended Olympian Michael Phelps on Monday after he was arrested for driving under the influence on September 30. Phelps will be banned from competing in US-sanctioned swimming events for reportedly violating the organization’s code of conduct.

Phelps was reportedly six months into a comeback after going into a two-year hiatus post-2012 Olympics. The champion swimmer is considered the most decorated Olympian of all time, garnering a record 8 gold medals in 2012 Summer Olympics alone. His attempted return to competitive swimming is now on hold for six months, according to the decision made by USA Swimming, which also stipulates the withdrawal of Phelps’s stipend for that period.

Michael Phelps is facing a steep punishment and will miss the 2015 world championships: http://t.co/gzMaPzr0oQ pic.twitter.com/3ZFSiafzFG

— CNN (@CNN) October 7, 2014

Among the sanctions Phelps faces is his exclusion from competing in the 2015 FINA World Swimming Championships in Russia next August. “Michael’s conduct was serious and required significant consequences,” said USA Swimming Executive Director Chuck Wielgus in a statement.

On September 30, Phelps reportedly drove 85 mph in a 45 mph lane and crossed double lane lines in the Fort McHenry Tunnel on Interstate 95 in Baltimore. He has been charged with driving under the influence, excessive speed and crossing double lane lines, with November 19 set for his trial.

Phelps took to Twitter on Sunday, October 5 to apologize for his conduct. In a series of tweets, he said, “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. 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.”

A spokesman at Octagon, the group representing Phelps, said that the swimmer has accepted USA Swimming’s sanctions and is taking steps to address the consequences of his actions. Phelps has reportedly checked himself into rehab for six weeks.