Mexico's Julio Cesar Chavez Jnr tested positive for marijuana after losing his World Boxing Council middleweight crown to Argentina's Sergio Martinez, promoter Bob Arum told reporters on Thursday.
The Los Angeles Times and ESPN reported that the Nevada State Athletic Commission told Arum's Top Rank firm of Chavez Jnr's urine test results after the Mexican's unanimous decision defeat last Saturday in Las Vegas.
The Mexican fighter faces up to a one-year suspension or possible revocation of his boxing license and a fine that could take all of his $3 million purse from the bout from the Nevada authorities.
A factor that will weigh into consideration of Chavez Jnr's punishment is a prior positive doping test for the Mexican in Nevada.
In 2009, he tested positive for a diuretic and was hit with a seven-month ban as well as stripped of a victory and fined $10,000 -- 10 percent of that fight's paycheck.
Pre-fight test results have not yet been received by Nevada officials, who Arum plans to seek leniency from because marijuana is a recreational drug and not a performance-enhancing substnce.
"You certainly worry about the repercussions, but we have a great commission in Nevada that understands what the social issues are," Arum told the Times. "As far as I'm concerned marijuana should be legal.
"I'm making a moral judgment. It has therapeutic effects. I'm not going to step back on this one: I don't think there's anything wrong with marijuana and if I had a vote I would vote to legalize it."
Arum told the Times that Chavez Jnr smoked marijuana to help him sleep but that such a benefit did not make the Mexican a dope cheat.
"I can't really get excited about it. There's no promoter in boxing who could pass the marijuana test, including myself," Arum told ESPN.
"If there was a trace of marijuana, to me, it's not the same as using a performance-enhancing drug. That is cheating."
Chavez Jnr fell to 46-1-1 after judges awarded Martinez, 50-2-2, the victory by scores of 118-109, 118-109 and 117-110.
"Of course, we're disappointed in him," Arum told ESPN. "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."
Chavez was arrested on a drunken driving charge last January just two weeks before a successful title defense. He reached a plea deal in that case three months ago that included three years of probation.