LOS ANGELES (AP) -- Jessica Hardy's first trip to the Olympics could be over before it begins.

The 21-year-old American swimmer was expected to be a medal threat in the 100 meter breaststroke, and to play an important part on the 400 meter free relay, and possibly the 400 medley relay.

But a person familiar with drug test results tells The Associated Press that Hardy's "A" sample from the U.S. Olympic trials tested positive for a banned stimulant. That would leave her just two weeks to pursue any appeals.

A USA Swimming spokeswoman isn't commenting, but Hardy's agent says she denies taking anything. He says he's heard conflicting reports and calls the test results confusing.

If Hardy does appeal and loses, the U.S. would not be allowed to replace her on the roster.