Big-hitting American Dustin Johnson will miss September's Ryder Cup after announcing he is taking time out of the game to confront "personal challenges".
Johnson hopes the break will improve his "mental health, physical well-being and emotional foundation".
The 30-year-old will not play the US PGA Championship at Valhalla and will also miss the Ryder Cup at Gleneagles.
Johnson was the only unbeaten United States player when Europe triumphed at Medinah two years ago.
Johnson, who finished 12th at this summer's Open at Royal Liverpool, will take his leave of absence with immediate effect.
"I will use this time to seek professional help for personal challenges I have faced," he said.
"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 fulfil my potential and become a consistent champion."
Johnson also pleaded for privacy "as I embark on this mission of self-improvement".
As well as missing the final major of the year and the Gleneagles showdown, which runs from 26-28 September, Johnson will also sit out the lucrative PGA Tour play-off series.
Lying fifth for the nine automatic spots in the American team, he was virtually certain of his place in the US Ryder Cup side.
"We will certainly miss Dustin Johnson at Gleneagles, and we wish him the best," US captain Tom Watson said.
"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."
Johnson pulled out of the 2012 Masters citing a back injury caused by lifting a jet ski. He missed three months of the season.
The PGA Tour said: "We have nothing to add to Dustin's statement, but we wish him well and look forward to his return to the PGA Tour in the future."