Rafael Nadal has not played a match since his second-round loss to Lukas Rosol in June at Wimbledon. (NEIL TINGLE / AFP / Getty Images)

Tendinitis in his left knee didn’t heal in time to allow him to compete for Spain in the London Olympics and now it will not allow him to compete in the U.S. Open that begins Aug. 27. Nadal won the Open in 2010, completing a career Grand Slam.

“I am very sad to announce that I am not ready to play the US Open in NY,” Nadal said in a tweet this morning. “Thanks to my fans for their support and specially, the new yorkers.”

Nadal, the 2010 champion, has never missed the U.S. Open, but has not played a match since June 28, when he lost to Lukas Rosol, ranked 100th in the world. Nadal has won 11 Grand Slams, but his style of play exacts a toll, particularly on his knees.

Last month, he pulled out of the Olympics, citing a lack of conditioning.

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