SHANGHAI (AP) — Top-ranked Jannik Sinner has withdrawn from the Shanghai Masters as he deals with a knee problem.

Sinner has not played since beating Alexander Zverev in the Wimbledon final. He withdrew from the U.S. Open because of a right knee injury.

“Unfortunately, I won’t be able to play at the Rolex Shanghai Masters this year as I had hoped,” the Italian wrote on his Instagram account Saturday. “I always enjoy playing in front of the Shanghai fans and I’m very sorry that I won’t be able to do so next week. Thank you for all your support. I’m looking forward to seeing you again next year!”

Sinner announced last week that he wouldn’t be able to defend his China Open title in Beijing, saying “my knee is not there where I would like to be and I am not ready to compete yet, but I will do everything possible to be there on court as soon as I can.”