INDIAN WELLS, Calif. -- Second-seeded Martina Hingis was forced to withdraw from the doubles portion of the Indian Wells Masters on Thursday due to tendinitis in her right wrist, leaving her participation in the $2.1 million tournament in doubt.

According to the WTA, Hingis, the winner of two titles this season and a finalist at the Australian Open, sustained the injury while practicing.

Switzerland's Hingis, a former world No. 1, was to have the wrist examined by a tour doctor later Thursday to determine if she could still compete in the singles tournament.

Hingis, who received a first-round bye, is scheduled to meet Croatian qualifier Silvija Talaja in the second round either Friday or Saturday.

If Hingis does pull out it, will be another a major blow to tournament organizers with the three top draws in women's tennis, top-ranked Venus Williams, her sister and defending champion Serena, and Australian Open winner Jennifer Capriati, having all bypassed the event.

The tournament lost another popular attraction on Thursday when Russian Anna Kournikova, Hingis' doubles partner, crashed out in the opening round.