MONACO -- Two-time Grand Slam champion Carlos Alcaraz withdrew from the clay-court Monte Carlo Masters tournament on Tuesday because of a muscle injury to his right forearm.
The Wimbledon champion had been doing low-key training with strapping to his arm and announced that he is unable to play.
"I have been working in Monte Carlo and trying to recover until the last minute from an injured pronator teres in my right arm, but it was not possible and I cannot play," Alcaraz wrote on X, formerly known as Twitter.
"I was really looking forward to playing. ... See you next year."
The 20-year-old Spaniard was scheduled to play Felix Auger-Aliassime of Canada in the second round in only his second appearance at the tournament, after also pulling out last year with injury. Auger-Aliassime instead faces lucky loser Lorenzo Sonego of Italy.
Alcaraz reached the French Open semifinals last year, losing to Novak Djokovic, before beating him in the Wimbledon final.
After winning six titles last year, Alcaraz's only trophy so far this year was when he defended his title at Indian Wells, again beating former U.S. Open champion Daniil Medvedev in the final.