Julio Cesar Chavez Jr has been banned for nine months and fined $900,000 by the Nevada State Athletic Commission for failing a drug test.
The 27-year-old Mexican tested positive for marijuana after losing on points to Argentina's Sergio Martinez in their WBC middleweight title fight on September 15 in Las Vegas.
Chavez will regain his active status on June 15, but his lawyers have vowed to appeal what they consider is an excessive fine for what is not considered a performance enhancing drug.
The fine represents 30 per cent of Chavez's $3million purse for the Martinez fight.
The commission's decision took into account a failed doping test in 2009 by Chavez in Las Vegas for a banned diuretic.
Chavez was suspended seven months for that offence, which also resulted in a victory by Chavez over Troy Rowland being changed to a no-decision.
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