World number one Iga Swiatek of Poland withdrew from next week's WTA event in Toronto on Friday, citing fatigue from her run to a bronze medal at the Paris Olympics.

The five-time Grand Slam champion, who won her third consecutive French Open title earlier this year, beat Slovakia's Anna Karolina Schmiedlova 6-2, 6-1 to medal in France before saying she needed a rest.

"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 statement.

"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."

In all, six of the world's top-10 players were revealed on Friday as slipping the Canadian tune-up event for the US Open.

Wimbledon champion Barbora Krejcikova withdrew from Toronto with a thigh injury. The Czech, ranked 10th in the world, reached the quarter-finals in singles and doubles at Paris.

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

Also pulling out was fourth-ranked Elena Rybakina, still sidelined by acute bronchitis that kept her from playing in Paris.

"Despite my best efforts to recover in time, my current health condition does not allow me to compete at the level required," Rybakina said.

Others pulling out of the event included Italy's fifth-ranked Jasmine Paolini, Greece's eighth-ranked Maria Sakkari, ninth-ranked American Danielle Collins, 18th-ranked Czech Marketa Vondrousova and France's 26th-ranked Caroline Garcia.

"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," tournament director Karl Hale said.

Reigning US Open champion Coco Gauff, the world number two from the United States, and Aryna Sabalenka, the third-ranked Belarus star who lost to Gauff in last year's US Open final, are Toronto's top seeds.

As a result of the withdrawals, 2020 Australian Open champion Sofia Kenin and 2017 US Open champion Sloane Stephens advanced into Toronto's main draw, as did former world number one Karolina Pliskova.