Bethanie Mattek-Sands, the champion of the Olympic games in Rio de Janeiro in the mixed doubles, was seriously injured in the second round of Wimbledon.
At the beginning of the third set against Romanian woman Sorani Kirsty, she came to the net and fell, pointing to his knee.
Athlete medical support on the court for about 20 minutes.
An accurate diagnosis is not yet clear, but doctors suspect a torn knee ligaments.
The first set was won by the American 6:4, the second Romanian 7:6. In the third set, the score was 0:0.