No one should be surprised that Nick Diaz has once again failed a drug test for marijuana. His post-UFC 143 positive test results represent the second time he has failed a drug test in Nevada. Diaz infamously failed a drug test that turned his biggest career win over Takanori Gomi at Pride 33 into a No Contest. Diaz also forced the cancellation of a 2009 Strikeforce title fight against Jay Hieron when he failed to appear for a pre-fight drug test.

Going into the UFC 143 interim welterweight title bout with Carlos Condit, Diaz fans were sanguine about his use of marijuana and his ability to pass any drug tests. He fought B.J. Penn in Nevada at UFC 137 and passed his drug test with no problems. He fought for Strikeforce three times in 2010 with no problems. But the reefer iceberg was floating under the surface the whole time, waiting to sink his MMA fortunes.

This is the same Nick Diaz who told the LA Times in 2009, "I can pass a drug test in eight days with herbal cleansers. I drink 10 pounds of water and sweat out 10 pounds of water every day. I'll be fine."

This is the same guy whose response to the question of whether his pot smoking was getting in the way of his MMA career said, "Actually, on the contrary, my fight career has gotten in the way of my marijuana smoking.."

This 2007 Diaz interview with CBS Sports is even more over the top.

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Ben Fowlkes sums up the situation at MMA Fighting:

...most people in the MMA world probably don't care that he smokes weed. It's not giving him an unfair advantage over his opponents, and it isn't jeopardizing his health. I suppose you could argue that it makes him a poor role model for kids, but no more than fighters who like to knock back a few too many adult beverages at the after-parties, and certainly not more than those who abuse use steroids or other performance-enhancers (not to mention, Nick Diaz is your kid's role model? If so, you've got bigger issues coming your way real soon). But if some fighters can get permission to up their testosterone levels before a fight, why can't Diaz use something that helps him relax and enjoy Reno 911 re-runs? The answer is: because the athletic commission says he can't. Right or wrong, those are the rules, and Diaz knew it. The UFC might have been content to look the other way as long as he passed his drug tests, but the moment he fails to hold up his end of the bargain is the moment he has a problem.

Fowlkes brings up an excellent about about testosterone levels. It's ironic that fighters like Chael Sonnen, Dan Henderson, Nate Marquardt and Todd Duffee have been allowed to get prescriptions for testosterone replacement therapy (TRT) but Diaz, with his prescription for medical marijuana can't get a pass.

We'll turn to the issue of whether or not marijuana should be a prohibited substance tomorrow, but for now just know that it was only a matter of time before Diaz failed another piss test. It's utterly maddening for such a talented fighter, a man at the peak of his athletic abilities to be looking at losing up to a year of his fighting career over something so avoidable.

Diaz was already talking about retiring based on the judges' scores for the Condit fight, I can only imagine this doesn't make him want to reconsider that decision.

Nick, put down the pipe, MMA needs you back.

SBN coverage of UFC 143: Diaz vs. Condit