Thaigo Silva Admits To Failed Drug Test, Denies Using Banned Substance - FightLine.com We reported yesterday that the UFC light heavyweight bout between Thiago Silva and Quinton "Rampage" Jackson set for UFC 130 in May may be off. Of the fifteen fighters tested for performance enhancing drugs at UFC 125 last January, one fighter's results were uncleared. Silva's manager revealed yesterday that is was in fact his client's drug test which had not cleared. Silva admitted today to Tatame.com that one of his samples had tested positive, while the other tested negative. "My blood is clean," Silva told Tatame. "I haven't used anything." However, Nevada State Athletic Commission executive director Keith Kizer, who has yet to name Silva as being the fighter who was uncleared, said that they were still awaiting results of the other sample. Silva's UFC 125 fight with Brandon Vera was the light heavyweight's first after being forced to sit out for a year while mending a back injury. The American Top Team trained fighter dominated a seemingly focused and fired up Brandon Vera for the entirety of their three round fight. Silva's performance earned him a fight against former UFC light heavyweight champion Quinton "Rampage" Jackson, which is now in jeopardy.