American tennis phenom Coco Gauff will no longer compete at the Tokyo Olympics after testing positive for COVID-19, she announced on Twitter Saturday. 

"I am so disappointed to share the news that I have tested positive for COVID and won't be able to play at the Olympic Games in Tokyo," the 17-year-old wrote. "It has always been a dream of mine to represent USA at the Olympics, and I hope there will be many more chances for me to make this dream come true in the future. I want to wish TEAM USA best of luck and a safe games for every Olympian and the entire Olympic family."

After making it to the quarterfinals at Wimbledon in June, Gauff was the headliner on a United States roster that was ravaged by big-name opt-outs. On the women's side, top-ranked women Serena Williams and Sofia Kenin declined their invites to the Games, and on the men's side, the top three -- John Isner, Reilly Opelka and Taylor Fritz -- opted out. 

Jennifer Brady, Jessica Pegula and Alison Riske are the remaining women set to represent the U.S. in singles, and Tommy Paul, Frances Tiafoe, Tennys Sandgren and Marcos Giron will represent on the men's side. Nicole Melichar and Rio mixed doubles gold medalist Bethanie Mattek-Sands are the doubles-only picks, along with Rio mixed double silver medalist Rajeev Ram, and Austin Krajicek.

Tennis competition at the Tokyo Olympics gets underway on Friday, July 23 (Eastern Time).