MASON, Ohio -- Defending champion Victoria Azarenka has withdrawn from the Western & Southern Open because of a right knee injury.
The WTA says Azarenka withdrew after practicing on Tuesday. Azarenka was replaced in the draw by Mona Barthel.
Azarenka injured her knee in her first-round win at Wimbledon and played in two tournaments after the grass-court major.
She hopes to be ready for the US Open, which starts Aug. 25.
"I'm going to get more treatment and get more work done and should be good for the US Open," Azarenka said in a release. "I feel strongly that it's the best for me at this moment."
Information from The Associated Press was used in this report.