"I am very, very sad to report that I am just not ready to compete at the level required to win a Grand Slam," Sharapova's official website quotes her as saying.
The 21-year-old tennis player withdrew from the WTA Rogers Cup in Montreal last July because of a shoulder injury. The injury forced Sharapova, who began the year by winning the Grand Slam in Australia, to miss the U.S. Open, the 2008 Beijing Olympics and other major tennis events.
The former world No. 1, who is currently ranked 9th in the Women Tennis Association's ranking list, underwent shoulder surgery last year and announced her comeback in December.
"I have been working very hard over the past few weeks and my shoulder is doing great, but there is way more preparation and training needed to compete to win my fourth Grand Slam and I have just ran out of time," Sharapova said.
Craig Tiley, the director of the 2009 Australian Open tournament, said he was disappointed for the Russian and her fans as he knows how hard she had practiced recently to hit the courts in Melbourne.
"She played some amazing tennis on Rod Laver Arena last year and has a massive legion of fans in Australia. I know she has been working around the clock to try and get back from the shoulder injury. In the end, time beat her this year," the official website of the 2009 Australian Open quoted Tiley as saying.
"We wish her well with her return to tennis and look forward to seeing her back in Melbourne next year, Maria is always welcome here," Tiley said.
