Canadian Open

Swiatek, who became the first player from Poland to win an Olympic medal in tennis history at the Paris Games on Friday, withdrew due to fatigue. 

Meanwhile, Krejcikova, who returned to the top 10 in the world rankings after her success at the All England Club, cited a thigh injury for her decision not to travel to Canada.

"I'm sorry to announce that due to overall fatigue caused by the last couple of weeks on the court I need to withdraw from the tournament in Toronto," Swiatek said in a Tennis Canada news release.

"Due to an intense tennis schedule with the Olympics taking place this year and changing surfaces, I need more time to rest and recover in order to be ready to play the US swing in good health and at my best possible level."

Krejcikova was beaten in the quarter-finals in both the singles and doubles at the Games, and said she is looking after her health ahead of the U.S. Open.

"The past four weeks have been incredible; however, the intense schedule has taken a toll on my body, and I need to prioritise my health to ensure I can continue competing at my best," said Krejcikova.

"Thank you for your understanding and support, and I look forward to returning to the court soon."

Tennis Canada said other withdrawals included Jasmine Paolini, Maria Sakkari, Danielle Collins and Caroline Garcia following their participation in the Paris Olympics.

"We understand the unique honour of athletes in an individual sport representing their country at the Olympic Games and that players must do what is best for them in terms of their health, recovery and schedules," said Karl Hale, director of the Canadian Open.

Past grand slam champions Sofia Kenin and Slone Stephens moved into the main draw for the Toronto tournament.

The NBO's men's tournament in Montreal took a hit earlier this week with the announcement that both Novak Djokovic and Carlos Alcaraz would also be missing the event.