Tournament organizers say top-ranked Serena Williams has pulled out of the Pan Pacific Open, two months after surgery on her right foot.

Williams, who cut her foot on broken glass at a restaurant after winning Wimbledon, returned to practice earlier this month.

Williams was to head a strong field for the Sept. 26-Oct. 2 event, which includes defending champion Maria Sharapova. Others in the field include Wimbledon runner-up Vera Zvonareva, French Open champion Francesca Schiavone, Caroline Wozniacki and Jelena Jankovic.

After missing the U.S. Open, Williams said she wasn't sure when she'd return to competition. She added she plans to play for the United States in the Fed Cup final against Italy in November.