Hong Kong  - Maria Sharapova will miss a high-powered Hong Kong tune-up event for only the second time since 2004 after the reigning Australian Open champion was forced to withdraw due to lack of preparation.

The Russian revealed that she underwent arthroscopic surgery in October on her problem shoulder and was only able to return to the practise court in Los Angeles a few weeks ago.

As a result, the three-time Grand Slam winner says she won't be ready to play the January 7-10 JB Group Classic. She has been replaced in the field by Anna Chakvetadze.

"It's with much disappointment that I have to withdraw from Hong Kong. I've been using this event for the last five years to get match fit and ready for the new season, in fact Hong Kong has been successful in preparing me for the Australian Open," Sharapova said in a statement.

Also competing in the Europe v America v Russia v Pacific competition at Victoria Park are Serbia's world number one Jelena Jankovic and Wimbledon champion Venus Williams.

Sharapova played only two matches since Wimbledon as she finally quit to try and cure her chronic rotator cuff problem.

She still insists she will be fit to defend her Australian Open crown when the Grand Slam starts on January 19.

"I'm just not ready to play against the top class competition in Hong Kong, although I remain hopeful for Australia where I'm the defending champion. "It's been a very difficult decision, but I only started practicing 16 days ago."

Sharapova, who missed the Beijing Olympics and US Open, ended the season ranked ninth. (dpa)