Rafael Nadal pulled out of upcoming hard-court tournaments in Indian Wells, California, and Miami because of the left hip flexor injury that has sidelined him since the Australian Open.
The 22-time Grand Slam champion announced Tuesday on Twitter that he would not be competing in the two U.S. events.
"I am sad that I won't be able to compete at Indian Wells nor Miami," Nadal posted. "Very sad not to be there. I'll miss all my US fans but I hope to see them later this year during the summer swing."
Nadal said that he has started "rehab, gym and physiotherapy as instructed by the doctors" so that he can "come back in the best conditions."
Nadal is a three-time winner at the BNP Paribas Open in Indian Wells, where main draw play begins on March 8. He is a five-time runner-up but has never won the Miami Open, which starts on March 22.
After Miami, the men's tennis circuit shifts to the European red clay, leading up to the French Open in late May.
Nadal has won 14 of his major titles at Roland Garros, including last year while dealing with chronic pain in his left foot. He then made it to the semifinals at Wimbledon but did not play in that round at the All England Club because of an abdominal injury.
The 36-year-old from Spain hurt his hip flexor during a second-round loss at Melbourne Park to Mackenzie McDonald of the United States in January.
Nadal has lost seven of his past nine matches, dating to a fourth-round defeat at the US Open in September, and the former No. 1-ranked player slid to No. 8 in the ATP standings this week.
The Associated Press contributed to this report.