New Delhi, Jan. 6 -- Novak Djokovic withdrew from the Australian Open tuneup tournament in Adelaide, saying Monday that he isn't prepared to return to competition ahead of the year's first Grand Slam event.

"To all my fans in Adelaide, unfortunately I'm not quite physically ready to compete in the Adelaide International next week," Djokovic posted on social media. "It's personally very disappointing to me, as I have such great memories of winning the title there two years ago. I was really excited about returning as it truly felt like playing at home."

Djokovic, a 38-year-old with a men's-record 24 major singles championships, has not played an official match in nearly two full months. He defeated Lorenzo Musetti in the final of the Hel...