U.S. tennis player Coco Gauff has tested positive for the coronavirus, forcing her to pull out of the Tokyo Olympics. Gauff revealed her positive test in a tweet on Sunday. The 17-year-old is No. 25 in the WTA rankings. She lost in the fourth round at Wimbledon last month. The U.S. Tennis Association said it was saddened to learn that Gauff will be unable to participate in Tokyo.