Nery (24-0, 18 KOs), a 22-year-old southpaw from Mexico, won the 118-pound world title by fourth-round knockout of Yamanaka on Aug. 15 in Kyoto, Japan, but he failed a Voluntary Anti-Doping Association-administered drug test as part of the WBC's Clean Boxing Program. Nery tested positive for the banned substance zilpaterol in a sample provided on July 27 in Tijuana, Mexico, his hometown.
After investigating the matter, the WBC issued its ruling on Monday in which it said that it "cannot make a determination with sufficient certainty as to whether Mr. Nery's adverse finding was the result of intentional ingestion of a banned substance to improve performance. All information and facts lead to conclude that the adverse finding was due to consumption of contaminated food products."
The WBC said that Nery, who did not request that his "B" sample be tested, gave the organization a sworn statement in which he said he "ingested substantial amounts of beef and beef consommé daily as part of his dietary/training regime in Mexico during several weeks preceding the adverse finding. ... Mr. Nery and his camp have emphatically denied taking any performance enhancing drugs or any banned substance."
Zilpaterol, similar to the banned substance clenbuterol, has contaminated beef in Mexico and has been an issue for athletes there in terms of drug testing.
The WBC ruled that in addition to giving Yamanaka a rematch, VADA "shall design a specific random testing protocol for Mr. Nery at his own cost and expense. The VADA-designed protocol shall commence as soon as feasible after this ruling and shall continue for six months thereafter, or up to the date of the immediate rematch, whichever time is longer."
Further, the WBC said it will investigate the effect of contaminated beef products in test results and will make a formal request to the World Anti-Doping Association and VADA to establish specific measures and protocols to address clenbuterol and zilpaterol.
While awaiting the WBC's ruling, Nery signed to face former two-time world title challenger Artur Villanueva (31-2, 17 KOs), 28, of the Philippines, in a 10-round nontitle fight on Saturday (beIN Sports Espanol, 11 p.m. ET) at Gasmart Stadium in Tijuana. After that fight Nery will be obligated to face Yamanaka next.
Yamanaka (27-1-2, 19 KOs), 35, had made 12 previous successful title defenses when he faced Nery and was bidding for No. 13, which would have tied the Japanese record for world title defenses set by Hall of Fame former junior flyweight champion Yoko Gushiken, who established the mark in 1980.