Hardy's "A" sample from the recent US Olympic trials tested positive, the person said on Wednesday night. The person requested anonymity because he was not authorized to speak publicly.

The Swimming World magazine Web site first reported the positive doping test.

Mark Schubert, head coach and general manager of the US team, and Dave Salo, Hardy's personal coach at Southern California, did not immediately return phone messages left by the AP.

USA Swimming spokeswoman Jamie Olson declined to comment from the US team's training camp at Palo Alto, Calif.

The Web site nbcolympics.com reported Hardy's backup "B" sample also tested positive.

If so, the 21-year-old swimmer from Long Beach can pursue appeals with both the American Arbitration Association and the Court of Arbitration for Sport. With the Olympics two weeks away, Hardy could appeal directly to CAS, although its ruling would be final and binding.

Typically, a first-time doping offense results in a 2-year ban.

Hardy's name was among the 596 athletes officially entered into the Beijing Games on Wednesday by the U.S. Olympic Committee.

Hardy earned spots on her first Olympic team in her best event, the 100-meter breaststroke, and the 50 freestyle and 400 free relay.

"I don't think if you had told me a month ago that I would make it in all three of these events that I would have believed you," she said at the trials. "I'm expecting good things for sure."

In Beijing, Hardy was expected to be a medal threat in the 100 breast, and to play an important part on the 400 free relay, and possibly the 400 medley relay.

If she appealed and lost, Hardy would not be replaced on the US team because the deadline to do so was July 21.

That would leave 41-year-old Dara Torres in the 50 free and Megan Jendrick in the 100 breast as the single American entrants in those events.

Hardy burst onto the international scene at the 2005 world championships in Montreal, where she broke the world record in the 100 breast. Her time of 1 minute, 6.20 seconds still stands as the American record.