California - Rafael Nadal will head home after beating Juan Martin del Potro for the Indian Wells ATP Masters title on Sunday, skipping the Miami Masters to rest his knee.
Miami tournament officials confirmed that Nadal had withdrawn on Sunday, before he had wrapped up the Indian Wells title with a 4-6, 6-3, 6-4 victory over del Potro.
"The Sony Open has been notified by the ATP that Rafael Nadal has officially withdrawn for the event," a statement from organizers said.
Nadal said he'd been advised by doctors that - after reaching the final in four tournaments since returning from a seven-month absence rehabilitating his damaged left knee - he needed time to rest.
That will allow him to prepare for the upcoming European clay-court season capped by the French Open, where he claimed a seventh title last year.
"I cannot go to Miami," Nadal said. "I'm very sad for that. I'm very sorry for the organization of the tournament, and I'm very sorry for the fans."
Nadal has played four tournaments since he returned to action, reaching the final in all of them and winning three. It's a lot more tennis than he expected to be playing.
"We never thought we'd be able to play all matches possible since I came back," he said. "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."
Miami tournament director Adam Barrett said organizers were disappointed, "especially given his strong results since his return to the tour".
"We wish him well and hope to see him back in Miami next year," Barrett said.