Rafael Nadal's preparation for a tilt at a record-extending 15th French Open title suffered a blow when he announced Tuesday his withdrawal from the upcoming Monte Carlo Masters.
"Hi everyone, I'm still not ready to compete at the highest level," the 36-year-old Spaniard tweeted.
"I will not be able to play in one of the most important tournaments of my career, Monte Carlo."
The Monte Carlo tournament, which Nadal has won 11 times, begins on Saturday, while the French Open starts May 28.
Nadal said he was hoping to return soon from the hip flexor injury he sustained in the Australian Open in January, suffering a second round exit against Mackenzie McDonald.
The 22-time Grand Slam champion pulled out of hard-court tournaments at Indian Wells and Miami, with his sights set on a return at the start of the clay court season.
Record Monte Carlo Masters champion Nadal won the tournament eight consecutive times between 2005 and 2012.
After the tournament's director said Nadal was registered for this year's edition, the Spaniard last week denied he was set to participate.
"I don't know who gets this information, but obviously if it were true, I would confirm it, but, unfortunately, I cannot confirm it," said Nadal at an event.
"Things are moving day by day, and I don't say things that I can't fulfil."