The U.S. Open says that Rafael Nadal has withdrawn from the last Grand Slam tennis tournament of the year because of injury.

Citing left knee tendinitis, the third-ranked Nadal hasn't played a match since June 28, when he was upset in the second round of Wimbledon by 100th-ranked Lukas Rosol.

Nadal also pulled out of the London Olympics and a hard-court tuneup tournament in Cincinnati.

The Spaniard won the 2010 U.S. Open to complete a career Grand Slam and was the runner-up to Novak Djokovic last year.

U.S. Open tournament director David Brewer says in a statement Tuesday: "Rafa has informed us that he will not be ready to compete at the U.S. Open this year."

Play begins at Flushing Meadows on Aug. 27.