Nadal, who suffered the injury during practice, will have to wear a cast on his right wrist for two-to-three weeks, forcing him to withdraw from next week's Rogers Cup in Toronto and the following week's Cincinnati Open.
"Depending on the evolution of the injury that will be carefully followed by the doctors, including MRI tests, it will be decided then the return to competition, initially scheduled for the US Open," Nadal's publicist said in a statement.
The world number two, who won the Canadian and Cincinnati titles last year, felt pain during practice in Mallorca and tests later revealed the injury, according to his publicist.
The injury will delay Nadal's start to the North American hardcourt season and his preparations for the Aug. 25-Sept. 8 U.S. Open in Flushing Meadows.
"I'm extremely disappointed that I am unable to defend my Rogers Cup title this year," the 14-time grand slam winner said in a statement released by the tournament organisers.
"Unfortunately I injured myself yesterday during practice and after checking with my doctors I will have to stay out of competition for at least 2-3 weeks."
A three-time winner on the Canadian hardcourts, the event has traditionally marked the start of the Spaniard's buildup to Flushing Meadows and marks only the second time since he made his Rogers Cup in 2004 that he has missed the stop.
"We know Rafa is a fan favourite and our fans will be upset by his absence," said Karl Hale, Rogers Cup tournament director. "But we also know that if Rafa could play he would as he has a great respect for our event and his Canadian fans."
Even with Nadal's withdrawal the Rogers Cup has attracted a top field that includes world number one Novak Djokovic, 17-times grand slam champion Roger Federer and Canadian hopeful Milos Raonic.
With Nadal's withdrawal, two-times grand slam champion Andy Murray moves into the number eight seed, giving him a first-round bye.
- Sports & Recreation