LAS VEGAS >> UFC welterweight Nick Diaz tested positive for marijuana after his loss to Carlos Condit on Saturday night and faces disciplinary action, including a possible suspension and fine, the head of the Nevada Athletic Commission said Thursday.

“We’ll give Nick ample opportunity to provide any defense, if any, that he wants to,” Kizer said. 

Kizer said that in April 2007, Diaz lost his license for six months and was fined $3,000 after another positive marijuana test after a submission win over Takanori Gomi in the Pride Fighting Championships.

Two other fighters who were recently disciplined for testing positive for marijuana after fights were fined part of their payday and had their licenses suspended for one year, Kizer said.

It was not immediately clear how the test would affect Diaz’s standing in the UFC or plans for him to fight Condit again. 

“I am beyond disappointed that he tested positive for marijuana,” the organization’s president, Dana White, said in an emailed statement. “It is now in the hands of the Nevada State Athletic Commission.”

White said on Twitter on Wednesday that Condit agreed to a rematch of the co-main event at UFC 143. Diaz wanted the rematch that night, White said. Condit won the interim welterweight title and a shot at fighting Georges St-Pierre.

Diaz was visibly upset at the loss in the close fight and hinted at retirement.

“I’m not going to accept this as a loss,” Diaz said. “I think I’m done with this MMA stuff, I don’t think they can pay me enough to do this again.” 

The marijuana test would be the latest in a string of unpredictable moves from the talented, yet mercurial Diaz outside the ring.

Diaz was supposed to fight St-Pierre in September, but the UFC pulled him from the bout for disciplinary reasons after he didn’t show up to promotional news conferences in Toronto and Las Vegas without explanation. Condit was Diaz’s replacement but the fight never happened because St-Pierre got hurt.

White nearly cut Diaz entirely, but instead matched him up against B.J. Penn, a fight Diaz easily won.

In 2010, Diaz threw a punch at Jason “Mayhem” Miller that started a brawl in the cage after a CBS-televised Strikeforce event.