World number three golfer Ernie Els will miss the rest of the season after suffering a knee injury on a sailing holiday in the Mediterranean last week.
The 35-year-old South African triple major winner twisted his knee while playing with his children and had surgery on Thursday that will stop him playing for several months.
"As a result, I'm going to have to take a break from golf on the recommendation of my medical advisers," Els said on his website. "Basically it's the only sensible course of action, so that I can be sure of the promptest recovery period."
He will miss the final major of the year in two weeks' time, the US PGA Championship at Baltusrol, and US Tour commissioner Tim Fincham does not expect one of his prize assets to be available until next January.
"Our best wishes go to Ernie for a speedy recovery," said Fincham. "His presence will be missed for the remainder of this season and at the Presidents Cup [in September]."
"But we all know what a tough competitor he is, and I am sure he will want to rejoin the PGA Tour as soon as he can."
Els's joint American and European commitments were both World Championship events, the American Express, a title he was due to defend, and the NEC Invitational.
He will miss the Dunhill Links Championship on the European Tour and the World Matchplay Championship, in which he was going for a record seventh win.
Els will be missed at the Presidents Cup, where he has been a key member especially two years ago in a memorable half after a playoff with Tiger Woods at Fancourt, South Africa.
George O'Grady, executive director of the European Tour said: "Everyone in the world of golf will share Ernie's disappointment at this news. I think I speak for everyone in wishing him a prompt and speedy recovery."
