Russian tennis star Maria Sharapova Saturday withdrew from January's Brisbane International due to an ankle injury, but said she expected to be ready for the Australian Open later that month. Sharapova twisted her left ankle at the Pan Pacific Open tennis tournament in September and she is still troubled by the injury. "I was really looking forward to starting my 2012 season at the Brisbane International, which has a fantastic reputation as a great and welcoming event," Sharapova said in a statement. "Unfortunately my ankle is not 100 percent and I won't be able to make it this year." But the former Wimbledon, US Open and Australian Open champion said she was keen to compete at the Australian Open which gets underway in Melbourne on January 16. "I do expect to be ready for the year's first Grand Slam and I am really looking forward to competing on court," she said. The Brisbane International is a WTA and ATP tournament, running from January 1-8. On the women's side, Serena Williams, Samantha Stosur and Kim Clijsters are all confirmed starters.