Martina Hingis is to undergo ankle surgery on Monday and will miss the French Open.
A WTA Tour statement said several tests conducted in Zurich this week had revealed one torn and three loose ligaments in the Swiss's left ankle.
"I am obviously very disappointed that I will be unable to play in Paris," Hingis said in the statement.
"However I am hopeful that the surgery on Monday will go well and that I can look forward to a speedy recovery. I will just need some time to rest and start a rehabilitation programme."
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The statement said that speculation that the injury may be a career-threatening was "premature and unwarranted".
The French Open starts at Roland Garros later this month.