Serena Williams will miss the Australian Open in January after opting to give herself more time to recover from foot surgery.
The American, who has not played competitively since winning Wimbledon in July, has also withdrawn from the Hopman Cup, which acts as a warm-up event for the year's opening grand slam event in Melbourne.
She said: "As I continue to rehabilitate my foot after the second surgery last month, it is with the utmost regret that I am withdrawing from the Hopman Cup and the 2011 Australian Open Championships.
"As I recently learned, pushing myself back into my intense training too early only caused me further injury and damage.
"While I desperately want to be back on the court and competing in the first grand slam tournament of the year, it is imperative for my health that I continue to work with my doctors to ensure my foot heals properly.
"This decision, though heavy on my heart, is the right one. I am praying for a healthy recovery and I promise my Aussie fans and my fans around the world that I will be back better than ever as soon as I can be."
Williams sustained the injury after standing on broken glass at a restaurant shortly after claiming her 13th grand slam crown at Wimbledon.