World number two and China’s Li Na is set to miss the US Open with a knee injury.
The 32-year-old Li, winner of the first Grand Slam of 2014 in Melbourne, says she has been advised to take some time off court to recuperate from the injury.
She has targeted a return to action in September.
“Since March, I have been struggling with my knee and it is just not where I need it to be in order to play at the highest level,” Li wrote on her Facebook page.
“My medical team has advised me that I need to take some time off to rest my knee so it heals.”
Li, who won her other Grand Slam title at the 2011 French Open, was eliminated in the first round of the 2014 championship before losing in the third round at Wimbledon.
The US Open starts on 25 August in New York and Li will miss the WTA events in Montreal and Cincinnati as well.