(CBS Sports) — Under pressure from the Nevada State Athletic Commission following a pair of failed drug tests, Canelo Alvarez has withdrawn from his May 5 middleweight championship rematch against Gennady Golovkin in Las Vegas.

Golden Boy, Alvarez’s promoter, made the announcement Tuesday during a media conference call, just 32 days out from the fight.

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“I am truly shocked by what has happened,” Alvarez said through a translator. “I don’t want anyone to have doubts about my integrity. I have always been a clean fighter and will be a clean fighter.

“To my fans, I have not let you down. I will respect the sport and will always be a clean fighter.”

Alvarez (49-1-2, 34 KOs) tested positive for traces of the banned substance clenbuterol during tests administered by the Voluntary Anti-Doping Agency in Mexico on Feb. 17 and 20. His initial excuse of contaminated meat, which has been an ongoing problem in the country for athletes in all sports, was supported publicly by both the WBC and WBA.

“I know many can ask yourselves how this can happen if I didn’t intentionally take clenbuterol,” Alvarez said. “Unfortunately, there is a public problem in my country.”

Golovkin (37-0-1, 33 KOs), however, continued to push publicly for a resolution, calling Alvarez and promoter Oscar De La Hoya “liars” and “cheaters” during a series of angry interviews while Alvarez awaited a hearing with the commission.

NSAC followed through last week by filing a formal complaint against Alvarez, which further put the fight going off in doubt. A key part to the NSAC ruling was that even if Alvarez unknowingly ingested to substance, his two positive tests still count as an anti-doping policy.

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A hearing has been scheduled for April 18, where Alvarez could face as low as a one-year suspension, reduced to six months if he cooperates, should he be found guilty. If suspended, it would be retroactive to his first positive test, which would make him eligible to fight again on August 17.

“We are hoping Canelo would be cleared to fight sometime in the summer, allowing us to reschedule the [Golovkin] fight possibly sometime in August and September,” Golden Boy’s Eric Gomez said.

Alvarez and Golovkin fought to a disputed draw last September in their pay-per-view blockbuster, which produced a controversial decision (most felt Golovkin had won) that only fueled interest in the rematch.

The failed tests made Alvarez, 27, the highest profile fighter to do so this close to his prime. Because of that, Alvarez is hoping to clear his name and cited a trio of clean tests he produced in March after moving his camp to the United States.

“I am sad and I feel powerless that I can’t make this fight happen at this point,” Alvarez said. “I have informed the NSAC that I’m willing to do whatever I can at their request to prove that I am a clean fighter. I will do everything in my power to prove, without a doubt, that I never intentionally ingested clenbuterol. I have nothing to hide and I want to be transparent and open during these processes.”

Golovkin, 35, has maintained that should the fight be postponed, he is still hoping to defend his trio of middleweight titles on May 5 against a new opponent.

Brian Campbell

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