Rafael Nadal has withdrawn from the Rogers Cup and the Cincinnati Open with a wrist injury.

The Spanish world number two is the defending champion at both tournaments.

Nadal, 28, strained his wrist during a practice session on Tuesday and is expected to be out of action for at least three weeks.

"Unfortunately I injured my right wrist yesterday during practice and after the tests I have undergone today in Spain, including an MRI, and checking with my doctors, I will have to stay out of competition for at least two to three weeks," he said in an official statement.

"I'm extremely disappointed that I am unable to defend my titles and compete in Toronto and Cincinnati this year. I was looking forward to coming and playing again after my great results last year."

The Rogers Cup gets underway this weekend, while the Cincinnati Open begins on August 9.