Zirbel denies "knowingly" ingesting DHEA. "Unknowingly" a tough sell.

Dope, meaning clueless?

"I didn't knowingly ingest any DHEA," said American rider Tom Zirbel after his A sample came back positive from a WADA-accredited lab at the University of Utah. So, the only remaining option is what -- unknowingly?

The "unknowingly" option is always a hard one for Twisted Spoke. Top riders scrutinize every facet of their training including a near religious focus on their diet. They weigh their food, they count every calorie and obsess about the benefits of each bite. They're maniacally careful about what they put in their bodies. Unknowingly is just hard to swallow.

In Zibel's case, the unknowing excuse is doubly hard to accept. He claims, "I'm ignorant about these things, I didn't know what DHEA was until I was first notified about my A sample." These days any rider with half a brain has a basic understanding of what is and isn't on the banned substance list. A steroid like DHEA is in screaming capital letters that are hard to miss. It's the same multi-function steroid that ended Tyler Hamilton's career.

But the most damning unknowing is when Zirbil goes into further detail about hiring an expert to oversee the handling of his B sample. He said, "I have a chemistry back ground so I thought I could check things out as well.” Having a working knowledge of chemistry makes the unknowingly argument even more difficult to believe. The man is a dedicated professional athlete with an interest in chemistry in a sport with a pervasive and public doping problem and he's never heard of DHEA? That puts quite a strain on credulity.

If this weren't what seems like the 100th rider in the last 10 years to plead ignorance about a positive doping test result, we could perhaps say, yeah, maybe, somebody in a white lab coat messed up. It happens, everybody makes mistakes. The newspapers are filled with cautionary tales of botched procedures and medical malpractice horror stories.

It would be a tremendous misfortune and gross injustice if Tom Zirbel is innocent. He finished second to Dave Zabriskie twice at the USA time Trial championships. He had a new contract with Garmin-Transitions for the 2010 season. His results are now questioned, contract terminated, career hanging in the balance. There's lot of undoing in the unknowing.

"I won’t say that it’s out of the realm of possibility that I would walk away from this,” he said. “But I’m pretty irritated about everything. It’s too early to talk about this but if it’s two years I would be pretty bitter. I’m 31 and I have to start thinking about life after cycling anyway."

Sadly, it seems to Twisted Spoke that Zirbel has unknowingly repeated the same sad, ignominious mistake as many riders before him. We look forward to writing a full retraction and apology to Zirbel should his B sample come back negative.

In the meantime, we'll just say, welcome to retirement, Tom.