World number one Carlos Alcaraz will miss the Australian Open because of a leg injury.

The 19-year-old Spaniard, who won his maiden grand slam title at the US Open in September, revealed he suffered a muscle injury in his right leg during pre-season training.

"I had worked a lot to reach my best level in Australia. Unfortunately I won't be able to play either Kooyong (warm-up event) or the Australian Open," Alcaraz posted on social media.

"It's tough, but I have to be optimistic, recover and look ahead. See you in 2024 Australian Open."

Alcaraz's withdrawal means his countryman, reigning champion Rafael Nadal, will be promoted to top seed for his title defence when the season's first grand slam gets under way in Melbourne on January 16.