MONTREAL -- Naomi Osaka pulled out of the National Bank Open hard-court tuneup to be played in Montreal this month ahead of the US Open.
The tournament announced the withdrawals of Osaka and two other top-10 players who have won Grand Slam titles, Sofia Kenin and Iga Swiatek, on Tuesday.
Osaka is coming off a third-round loss at the Tokyo Olympics, where she had the honor of lighting the cauldron during the opening ceremony.
Before that, the 23-year-old Osaka had not competed anywhere since withdrawing before her second-round match at the French Open, citing the need for a mental health break. She also sat out Wimbledon entirely.
She is ranked No. 2 and is the owner of four major championships, all on hard courts, including this year's Australian Open.
The fourth-ranked Kenin, who won the 2020 Australian Open, has been sidelined by a foot injury since Wimbledon.
No. 8 Swiatek, last year's French Open champion, lost in the second round of the Olympics.
The tournament begins Aug. 9.
The US Open, the year's last major championship, starts Aug. 30 in New York.