Palo Alto, CA -- (Sports Network) - A doping violation could put a damper on the U.S. swimming medal hopes at the Olympics.

The Web site of nbcolympics.com and Swimming World Magazine both report Jessica Hardy has tested positive for a banned substance. Hardy is reportedly no longer at the U.S. swimming team's training camp.

The NBC site reports Hardy's A and B samples both came back positive.

The 21-year-old Hardy is due to represent the U.S. in Beijing in the 100 meter breaststroke and the 50-meter freestyle as well as at least one relay.

Because the deadline for the U.S. to add new swimmers to the Olympic roster has already passed, if Hardy is banned, the team will have to replace her with current athletes already on the squad. Kara Lynn Joyce would likely get a spot in the 50 free, while Rebecca Soni could be added to the 100 breaststroke.

Hardy broke the American record for the 50 free in the semifinals of the recent Olympic trials before 41-year-old Dara Torres eclipsed the mark.