Eugenie Bouchard still dealing with lingering effects of concussion

Eugenie Bouchard has withdrawn from next week's Tokyo Open, citing lingering effects from a concussion she suffered at the US Open.

"I'm really disappointed to withdraw from the Toray Pan Pacific Open, but I haven't sufficiently recovered from the concussion I sustained while competing at the US Open," Bouchard said in a statement posted by the WTA on Thursday. "My fans in Japan are very special to me. I love playing there and I can't wait to go back next year."

The Canadian withdrew from the US Open before her fourth-round match after falling and hitting her head in the locker room at the National Tennis Center. Bouchard was evaluated by tournament medical staff before officially withdrawing.

Bouchard's injury occurred as she was returning to the locker room to take an ice bath late after her news conference on Sept. 4 following her mixed doubles victory with Nick Kyrgios, a source close to Bouchard told ESPN's Jane McManus. Bouchard had also defeated Dominika Cibulkova 7-6 (9), 4-6, 6-3 in singles to reach the fourth round earlier in the day.

It was late, and the women's locker room was dark, so Bouchard felt around to find the light. According to the source, there was water on the floor, and Bouchard slipped, falling backward and landing on the back of her head. She went to the emergency room that night. After she was released, there was concern that playing a tennis match would not help her recovery and that she needed rest, the source said.

Bouchard had been hopeful she'd be able to play despite withdrawing from the ladies and mixed doubles tournaments on Saturday. Her team had been assessing the situation and her options all day, but she could not ignore the symptoms of the injury and withdrew from her fourth-round singles match. She was slated to play Roberta Vinci, who went on to upset Serena Williams in the semifinals.

Bouchard is next scheduled to play at the Dongfeng Motor Wuhan Open, which begins Sept. 27 in China.

Information from ESPN's Jane McManus was used in this report.