Former UFC heavyweight champion Brock Lesnar was issued a temporary suspension on Tuesday by the Nevada Athletic Commission (NAC), marking the first step in the adjudication process for Lesnar's multiple UFC 200 drug testing failures.

Lesnar, 39, tested positive for the banned substance hydroxy-clomiphene, an anti-estrogen agent, in an out-of-competition drug test administered by USADA on June 28 as well as an in-competition test taken at UFC 200. The WWE superstar was tested by USADA eight times in advance of his July 9 fight against Mark Hunt, which Lesnar won via unanimous decision, though the positive test results only came back after UFC 200.

Lesnar is expected to receive a formal hearing with the NAC at a later date. He faces a potential two-year suspension from both USADA and the NAC, as well as fines from the latter -- a sentence that would effectively end his mixed martial arts career.

"To my fans that watch me in the octagon, I thank them for their support," Lesnar told TMZ Sports at a recent media event. "This has been a bumpy road. I'm gonna get through this alright. And there will be a day, maybe, that they'll see me back in the octagon."

Lesnar (6-3) is a WWE crossover star who captured the UFC heavyweight title with a resounding victory over Randy Couture in 2008. Lesnar defended his title twice, defeating Frank Mir and Shane Carwin, before suffering back-to-back losses against Cain Velasquez and Alistair Overeem, as well as two separate bouts with diverticulitis, then retiring back to WWE.

Nearly five years after his retirement, Lesnar made a surprise return to fight top-10 heavyweight contender Hunt at UFC 200. Lesnar won the bout via unanimous decision, but tested positive for anti-estrogen agents in two drug tests revealed in the weeks after the fight, prompting a furious Hunt to rally against the UFC and USADA for waiving the four-month testing window required of returning athletes by USADA in order to slot Lesnar into UFC 200 on a condensed timetable.