Former middleweight titlist Julio Cesar Chavez Jr., who lost a lopsided decision to lineal champion Sergio Martinez despite a dramatic 12th-round comeback on Saturday night at the Thomas & Mack Center in Las Vegas, has tested positive for marijuana.
Chavez's post-fight urine sample came back positive, Top Rank's Bob Arum told ESPN.com on Wednesday.
"The commission let (Top Rank's Carl) Moretti know (Tuesday) night that he tested positive," Arum said. "I can't really get excited about it. There's no promoter in boxing who could pass the marijuana test, including myself.
"Julio is going to have to explain to the commission what happened and the commission will be guided accordingly. If there was a trace of marijuana, to me, it's not the same as using a performance-enhancing drug. That is cheating."
Marijuana, of course, is illegal in addition to being banned by the commission.
The Nevada State Athletic Commission normally does not release any test results until all of them are back from a card, but executive director Keith Kizer confirmed there had been one positive drug test from the Martinez-Chavez card.
Kizer said that while the commission has back all of the post-fight urine tests, which test for drugs, it is still waiting for results from the pre-fight urine tests. Those tests are for steroids and should be back in a few days, Kizer said.
"I will release the results from the event once I get them all back, but Top Rank's statement is an accurate reflection of the conversation I had with them (Tuesday)," Kizer said. "We had a positive test, one from that card."
This is Chavez's second positive test for a banned substance and third involving a banned substance or alcohol.
"Of course, we're disappointed in him," Arum said. "Hopefully, he can learn a lesson here and next time get in top shape for the fight. But it shows you the immaturity here. He needs to grow up."
In November 2009, Chavez tested positive for Furosemide -- a diuretic typically used to help cut weight or used as a masking agent for steroids -- in conjunction with his fight against Troy Rowland, which took place on the Manny Pacquiao-Miguel Cotto undercard at the MGM Grand in Las Vegas.
The commission suspended Chavez for seven months and fined him $10,000 (10 percent of his $100,000 purse). The fight result, originally a lopsided decision win for Chavez, was changed to a no-decision.
In January, Chavez (46-1-1, 32 KOs) was arrested on a DUI charge in Los Angeles, where he was training, just two weeks before he defeated Marco Antonio Rubio in San Antonio to retain his version of the 160-pound title. Chavez reached a plea deal in the case in June, which included three years of probation.
The Nevada commission will file a complaint against Chavez and could fine him up to 100 percent of his $3 million purse (although that is unlikely) and suspend him for up to a year or even revoke his license. If Nevada suspends Chavez, other states are required to honor the suspension under federal law.
Chavez's past positive test in Nevada likely will be taken into consideration when he is punished.
"In the past we have had three fighters who have been repeat offenders and the commission has found that to be an aggravating factor and enhanced the penalty," Kizer said.
Considering Chavez likely will be suspended for a lengthy period of time, that would rule out a rematch, which both camps are interested in, for the first half of 2013. Last Saturday's HBO PPV fight far exceeded initial projections. Arum said they worked out their deals based on the prediction that the fight would do between 250,000 and 350,000 PPV buys. Although Top Rank and HBO are still a few days away from reporting the figures, Arum said, based on initial numbers they have from satellite services and select cable systems, the fight likely will come close to 500,000 units with a chance to do 600,000.
Martinez (50-2-2, 28 KOs) dominated the first 11 rounds of the fight, but in the 12th round, Chavez came to life. He badly hurt Martinez, knocked him down and nearly finished him, although Martinez fought back and made it through the rest of what will likely be the round of the year to win a unanimous decision on scores of 118-109, 118-109 and 117-110.