KEY BISCAYNE, Fla. -- Rafael Nadal has withdrawn from the Sony Open that begins Monday in Key Biscayne, Fla., to rest his left knee.

He won the BNP Paribas Open on Sunday at Indian Wells, Calif., his third title in four tournaments since returning in February after seven months off with the knee injury.

"I'm very sorry for the organization of the tournament and I'm very sorry for the fans, but we never thought we'd be able to play all matches possible since I came back," Nadal said after defeating Juan Martin del Potro in three sets.

"The doctors recommend me to be back home for a few weeks and rest a little bit and keep practicing the right way. I need more power on the left leg quadriceps, so I need to keep working hard. The competition is hard for the body, so after four fantastic weeks I can't go to Miami. I need to prepare and rest for the next one."

Sony Open tournament director Adam Barrett says he's disappointed that Nadal won't be competing in Miami.

Nadal says he next plans to play on clay in Monte Carlo in mid-April, followed by two tournaments in his home country of Spain - Barcelona and Madrid - and then Rome.