German No.1 Andrea Petkovic will miss both the French Open and Wimbledon after tearing ankle ligaments less than a week after making her comeback from a back injury.
The 24-year-old, ranked 12th in the world, badly twisted her right ankle during her second-round tie against world No.1 Victoria Azarenka at the Stuttgart WTA tournament as she slid to reach a ball on Thursday night.
Scans at hospital in Stuttgart on Friday revealed she has torn two ligaments, and damaged a third, in her right ankle and may need an operation.
She will be out for around three months, having only returned on Sunday from a three-month break after suffering with back problems.
She also tore the ACL ligaments in her right knee in 2008.
It means she will definitely miss Grand Slam tournaments at Roland Garros, which starts in Paris on May 27, and Wimbledon, which begins June 25.
She may yet be able to play at the London Olympics which take place from July 27-August 12.
"I have to start the recovery process all over again," said Petkovic, who reached the quarter-finals of last season's Australian, French and US Opens, as well as the third round at Wimbledon.
"As a professional athlete, there are always setbacks, but an injury like this is painful.
"I have twice now fought back after a serious injury and will now do it a third time.
"I just hope I have enough fighting spirit left to put that to the test."
Having pulled out of January's Australian Open with back problems, Petkovic only returned last Sunday as Germany lost their Fed Cup World Group playoff 3-2 to Australia.