American Dustin Johnson will miss the Ryder Cup after announcing he is to take a break from golf and seek "professional help for personal challenges" he has faced.
Johnson, who won all three of his matches at Medinah in 2012, will also not contest next week's US PGA Championship at Valhalla, after which the nine automatic qualifiers for Tom Watson's team will be finalised.
The 30-year-old had been fifth in the standings and looked certain to make his third consecutive appearance in the event at Gleneagles. With Johnson now out of the running, everyone below him in the table moves up a place.
Watson said in a statement: "We will certainly miss Dustin Johnson at Gleneagles and we wish him the best. As one of the longest hitters in the game with an undefeated record of 3-0 at Medinah in 2012, he has clearly been an asset for the United States team.
"That said, the United States is a team with an abundance of talent. I am looking forward to teeing it up alongside those players in the PGA Championship at Valhalla and finding out, along with everyone else, which players qualify for the team based on points."
Johnson, who was joint fourth in the US Open and joint 12th in the Open Championship this season, released a statement through his management company on Thursday which read: "I am taking a leave of absence from professional golf, effective immediately.
"I will use this time to seek professional help for personal challenges I have faced.
"By committing the time and resources necessary to improve my mental health, physical well-being and emotional foundation, I am confident that I will be better equipped to fulfill my potential and become a consistent champion.
"I respectfully ask my fans, well-wishers and the media for privacy as I embark upon this mission of self-improvement."
The PGA Tour released a statement which read: "We have nothing to add to Dustin's statement but wish him well and look forward to his return to the PGA Tour in the future."
European Ryder Cup captain Paul McGinley, commentating on the WGC-Bridgestone Invitational for Sky Sports, felt Johnson's statement would simply lead to a "lot of speculation and rumours".
"Things will be said that are not true," McGinley added. "It's much better for everyone if there is clarity. If something has gone wrong and he has been misbehaving, let's put it out on the table and get it dealt with and move forward."
In May 2012, Johnson's agent David Winkle insisted his client had not been serving a drugs suspension from the PGA Tour when he spent three months out of the game.
In a Q&A conducted by Golf Channel.com in December last year, Johnson himself said he had never been punished or reprimanded for any kind of drugs violation.