"My knee is not where I want it to be and I'm not ready to compete yet, but I'll do everything I can to be back as soon as possible," the 25-year-old tennis star writes on X.
The five-time Grand Slam winner has not played since his victory at Wimbledon in July.
Sinner's continued absence means that new world number two Alexander Zverev can move closer to the top of the world rankings going forward. The German, who has won both the French Championships and the US Open this year, is entered in tournaments in Beijing, Shanghai and Vienna in the near future.
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