Diaz is set to feature against Jorge Masvidal in the main event on November 2 in New York.
But he says he is now out after testing positive for a banned substance.
“Im not gonna make it out to NYC for fight week next week because they say I tested with elevated levels that they say might be from some tainted supplements,” Diaz wrote on Twitter.
“I call false on that cause I only take Whole Food or natural food supplements. I don’t even eat meat.
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“So until UFC, Usada or whoever is F***ING with me Fixes it, I won’t be competing.”
Conor McGregor reacts
It didn’t take long for McGregor, who fought Diaz at UFC 196 and UFC 202, to react in a since-deleted tweet.
Diaz referred to himself as the “realest baddest mother f***er in the game”. McGregor took aim at that statement in his tweet.
“There’s only one Bad Mother F***er in this game and he is the weight jumping, sport crossing, country invading, whiskey drinking Irish animal typing this tweet right now,” the Notorious said.
“Right here from his presidential suite at the Ritz Carlton in downtown Moscow.
“See you all soon.”
McGregor announced that he would be returning to the UFC on January 18 during a press conference in Moscow on Thursday.
The Irishman is eager to take on the winner of Khabib Nurmagomedov and Tony Ferguson’s UFC Lightweight title bout.
McGregor lost to Nurmagomedov at UFC 229, of course, and wants another shot at the unbeaten Dagestani fighter.
“We want this bout in Moscow. The people in Russia deserve this bout to take place. The people of the world deserve this bout to take place,” McGregor said.
“There is an inevitable rematch, it is a rematch that I will come in sharp, fresh.
“I will have no injuries, I will have no alcohol, I will have no outside influences, I will be fully focused, exactly what the people deserve. And we will settle it once and for all.”News Now - Sport News