Elite players led by world No.1 Roger Federer at the Cincinnati Masters expressed their concern on Wednesday that Rafael Nadal will miss the US Open due to left knee tendinitis.

“It’s not a surprise because I wrote him and he told me it wasn’t looking good at all,” said top-seeded Federer.

“But obviously when it’s official, it’s disappointing for tennis – there’s no doubt about it.

“I would love to have him in the draw. With 12 days before the Open, you figure he might still have time to fix what he has to fix to get ready.

“There is obviously the whole debate going on if he is going to come back for this year.

“I hope in hindsight this is a very smart decision by him. But it’s obviously a big blow and disappointing news for the tennis world.”

Those sentiments were echoed by world No.2 Novak Djokovic and fourth-ranked Olympic gold medallist Andy Murray.

“He’s a great competitor,” Djokovic said. “I’m sure that if he was able to perform in the US Open, he would come. So I wish him a quick recovery.”

Murray, who has been dealing with a knee problem of his own over the past week or so, was equally sympathetic.

“I’m disappointed for him – it’s obviously tough. He’s had trouble with his knees in the past. So I hope he can rest, doesn’t come back too early and gets them fixed so he can get back to playing his best tennis.”

Nadal hasn’t played since losing in the second round at Wimbledon almost two months ago and confirmed his scratching on Wednesday.

“Rafa has informed us that he will not be ready to compete at the US Open this year and has withdrawn from the tournament,” US Open tournament director David Brewer said in a statement.

“We hope to see him back on the court soon and look forward to his return to New York next year.”

Nadal had been dropping hints for weeks that his condition might not be improving.

The Spanish world No.3 played his last match on June 28, losing in the Wimbledon second round to Czech Lukas Rosol.

“I am very sad to announce that I am still not ready to play and have to withdraw from this year’s US Open in NYC,” said Nadal.

“I’m sorry since I always found great crowds and great support, but I have to continue with my recoup and preparation to be ready to play in the right conditions. I want to say hi and thanks to all the fans, in particular to the New Yorkers. I’ll miss you all this year at the Open.”

The Spaniard won the title in 2010 and played the final last year against Djokovic.

The US Open, the final grand slam of the season, starts on August 27.