Rafael Nadal withdrew Wednesday from U.S. Open tuneups in Toronto and Cincinnati because of a right wrist injury, putting in doubt his status for a title defense at the year's last Grand Slam tournament.
The second-ranked Nadal plays left-handed, but he uses a two-handed backhand.
He said in a statement issued by the Toronto tournament that he injured himself Tuesday.
In a posting on Facebook, Nadal said he is "disappointed" that he can't play the next two weeks but adds, "I expect to be well for the U.S. Open."
Nadal's manager, Benito Perez-Barbadillo, wrote in an emailed release that the Spaniard was hurt in practice on his home island of Mallorca while getting ready for the North American hard-court circuit.
Perez-Barbadillo said that doctors determined Wednesday that Nadal will need to wear a cast on his wrist for two to three weeks and the initial prognosis is for him to be able to return to action at the U.S. Open, which begins Aug. 25. But doctors will keep tabs on the injury, including with MRI exams, and then decide when Nadal can play again.
The Toronto tournament begins Monday, and the Cincinnati tournament starts Aug. 11. Nadal won both of those events last year (when the Canadian tournament was held in Montreal). They would have represented his hard-court preparation for this year's U.S. Open.
Nadal won his second championship at Flushing Meadows in 2013. That is part of his collection of 14 Grand Slam titles, tied with Pete Sampras for second in the history of men's tennis, trailing only Roger Federer's record of 17.
Nadal is 44-8 with four titles in 2014, including his record ninth French Open trophy.
He hasn't competed since losing in the fourth round of Wimbledon to 19-year-old Nick Kyrgios in four sets on July 1.
Nadal has reached the final in his last three appearances at the U.S. Open, beating Novak Djokovic to win the titles in 2010 and last year, and losing to Djokovic in 2011. Nadal missed the tournament in 2012, part of an extended absence because of a knee injury.
He missed a chance to defend his 2008 Wimbledon championship in 2009, because of knee problems.