Rafael Nadal has withdrawn from the Masters 1000 events at Indian Wells and Miami because of injury.
The 22-time Grand Slam champion was expected to be out for six to eight weeks with a hip injury that hampered his defeat by Mackenzie McDonald.
"We wish Rafa continued healing and hope to see him back next year," said Indian Wells director Tommy Haas.
Nadal won at the California event - which starts next week - in 2007, 2009 and 2013, and lost in last year's final to American Taylor Fritz.
Nadal has been mostly limited to physio and gym work in recent weeks, but was able to begin a gradual return to the court on Monday.
He will also miss the Miami Open in three weeks' time.
Nadal's next target is likely to be the Monte Carlo Masters, where he is an 11-time champion.
The first major event of the European clay court season begins on 9 April.
"Took my time off, started rehab, gym and physiotherapy as instructed by the doctors. Getting ready to come back in the best conditions," Nadal tweeted.
"I am sad that I won't be able to compete at Indian Wells nor Miami. 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," he added.
Meanwhile, Cameron Norrie and Carlos Alcaraz have both withdrawn from this week's Mexican Open - having contested two finals in a row on the ATP Tour.
Norrie has cited fatigue, while Spaniard Alcaraz is dealing with the leg injury which was evident in his defeat to the British number one in Sunday's Rio Open final.