Laura Siegemund is set to miss all three of the year's remaining grand slams after rupturing the anterior cruciate ligament in her right knee.
Siegemund sustained the injury at the Nurnberger Versicherungscup on Wednesday, when she took a heavy fall in the second set of a match against Barbora Krejcikova, forcing her to retire.
In a statement on her official Facebook page on Thursday, the world number 32 - who won last month's Stuttgart Open - confirmed she had suffered severe damage.
Siegemund wrote: "As some of you might have heard already, I injured my knee in a match yesterday at the WTA tournament in Nurnberg.
"The diagnosis is a rupture of the ACL. Of course I am disappointed and sad not to be able to compete in the upcoming tournaments - especially the French Open, where I was looking forward very much to play - but I am focused on a quick recovery now and will put all my energy into that.
"I hope to see you all again asap."
Liebe Fans, wie ihr vielleicht mitbekommen habt, habe ich mich gestern in meinem Match beim Nürnberger Versicherungscup...
Posted by Laura Siegemund on Thursday, 25 May 2017
As a result of her injury, Siegemund will not be present at the French Open, which starts on Sunday, or Wimbledon. The prospects of her recovering in time to feature in the US Open appear remote.