Dr. Heinz Buehlmann told Swiss radio he was pleased with the result of the 90-minute operation, during which he repaired one torn and three loose ligaments in Hingis' left ankle.

He said he expected Hingis to make a swift recovery, but that she would need ''6-to-8 weeks of rest to help the healing process.''

Hingis also was suffering from severe pain in her feet, left knee and left hip, which forced her to stop playing or practicing.

Buehlmann said Monday that he wanted to wait until the post-operation swelling had gone down before making a final assessment of Hingis' chances of an early return to tennis. He said her career still could be threatened if the pain in her feet and joints returned.

Last week, Buehlmann said he feared the ligament damage -- which he said was ``complex'' -- could end the 21-year-old Hingis' playing career.

On Saturday, after two days of tests at the Bethanienheim clinic in Zurich, Buehlmann said the outlook was positive, with Hingis likely to resume light water training and cycling in about three weeks -- and be back on the tennis court in three months.

Buehlmann also operated on Hingis' right foot in October last year, after which the Swiss star was out of action for two months.

The ankle injury already has forced Hingis to miss the German Open and last week's Italian Open.

On Friday, the WTA said the player also would miss the French Open, which begins May 27.

The French Open will be the first Grand Slam tournament Hingis has missed since turning professional in 1994, breaking a streak of 29 straight appearances.

Hingis has won five Grand Slam tournaments in her career.

Last week, the player's mother, Melanie Molitor, said her daughter's injuries may have been caused by the shoes that Hingis wore for tennis from the age of 11 until three years ago.

Last June, Hingis filed a $40 million lawsuit against Italian sportswear manufacturer Sergio Tacchini, with whom she had a five-year sponsorship deal. She claimed that she had been provided with ``defective'' shoes ``unsuitable for competition,'' forcing her to withdraw from several tournaments.

Sergio Tacchini said the claims had been made only so Hingis could avoid paying damages for breaching her contract with the company.