Thailand's Ratchanok Inthanon, the women's singles top seed at the 2011 Yonex-Sunrise Vietnam Open Grand Prix, has withdrawn from the August 22-28 event.
The Thai team's coaching staff made the announcement at a meeting in Ho Chi Minh City on Monday without giving a reason.
Sixteen-year-old Inthanon, Thailand's number two female player, is the defending champ at this event and also the reigning Youth Olympics champion.
When she competed at the Yonex-Sunrise Vietnam Open Grand Prix last year, she was not among the world top 50 but she is ranked 12th now.
Huynh Ngoc Lien, Deputy Manager of the organizing committee of the 2011 Yonex-Sunrise Vietnam Open Grand Prix, said the committee will send a report on the case to the Badminton World Federation (BWF).
It is likely Inthanon will be penalized by federation because the Yonex-Sunrise Vietnam Open Grand Prix is part of BWF tournaments.
Inthanon's withdrawal in the final minute violates regulations that allow players to withdraw from a competition 15 days prior to the opening. Her withdrawal partially lessens the excitement of the event, Lien said.