Meanwhile, Venus Williams and Sofia Kenin will also be absent from the women’s draw next week, with seven-time Major champion Williams not giving a reason for her withdrawal.
Both have not played since Wimbledon, where the 41-year-old lost in the second round to Ons Jabeur.
Kenin has been sidelined by a foot injury she sustained in her second round loss to Madison Brengle.
“Unfortunately I had to make the difficult decision to withdraw from the Western & Southern Open next week,” Kenin said.
“I am rehabbing well in hopes to play the US Open later this month. I feel another week of recovery is necessary.”
