According to a story over at Podium Insight, Tom Zirbel's A sample at the U.S. Pro time trial championship tested positive. The Team Bissell rider placed second in the championship event behind David Zabriskie of Garmin-Slipstream. Zirbel tested positive for exogenous DHEA, a synthetic steroid. DHEA also figured in the case of Tyler Hamilton, who tested positive for the same substance in April 2009.
After his successes this season, Zirbel signed to ride with Garmin-Transitions for the coming season, but his absence from a recently published roster prompted questions about his status. Sunday, Zirbel released a statement in which he announced the A sample violation, and said he was waiting for the results of the B sample. He also said that while the US Pro TT was a "major objective," he would never compromise his integrity for "any bike race." He declined to speculate on how the positive test may have occured. Garmin-Transitions, meanwhile, has terminated the contract with Zirbel.
Zirbel's case marks the second doping problem for Team Bissell, who fired Kirk O'Bee in July of this year for an unspecified doping offense.
Photo, Christian Petersen, Getty Images Sport.