"I'm disappointed to have to withdraw from the Pan Pacific Open, which I was very much looking forward to playing this year," the American was quoted as saying.
"Unfortunately with the number of matches I have played throughout the summer I need more time to properly recover."
World number 19 Maria Kirilenko also confirmed she was withdrawing for the event after picking up an injury in her loss to 42-year-old Japanese veteran Kimiko Date-Krumm at WTA Seoul.
The pair are the latest high-profile withdrawal from the September 22-28 tournament after Russian Maria Sharapova also pulled out last week to recover from a right shoulder injury.
- Sports & Recreation
- Disease & Medical Conditions
- Maria Kirilenko
- Pan Pacific Open