Milos Raonic
FILE - In this July 7, 2021, file photo, Switzerland's Roger Federer wipes his brow during the men's singles quarterfinals match against Poland's Hubert Hurkacz on day nine of the Wimbledon Tennis Championships in London. Federer pulled out of the upcoming hard-court tournaments in Toronto and Cincinnati on Thursday, Aug. 5, 2021, citing lingering issues with his surgically repaired knee and shedding doubt on his status for the U.S. Open. (AP Photo/Kirsty Wigglesworth, File)
Citing knee, Federer out of Toronto, Cincinnati tournaments

By Howard Fendrich Aug. 05, 2021 02:51 PM EDT

File - In this Oct. 10, 2020, file photo, Sofia Kenin, of the United States, plays a shot against Poland's Iga Swiatek in the final match of the French Open tennis tournament at the Roland Garros stadium in Paris, France. Kenin is the top-seeded woman in Abu Dhabi, where the first women’s tour-level tennis event of 2021 begins main-draw play on Wednesday, Jan. 6, 2021. (AP Photo/Michel Euler, File)
TENNIS '21: COVID questions key; Nadal, Djokovic eye records

By Howard Fendrich Jan. 05, 2021 12:04 PM EST