Sources told FOX Sports those rumours were unfounded and discussions about Lesnar's walk out haven't happened yet, although anything is possible.
When Lesnar originally joined the UFC, he made the distinction not to blur the line between his performances in WWE and what he was doing in mixed martial arts.
While that distinction remains the same ahead of his next fight, it appears part of Lesnar's deal to return to the UFC may have also earned the WWE some extra promotion at the event July 9.
Following UFC 200, Lesnar is then expected to return to the WWE, where he will take part in SummerSlam on August 20.
Lesnar may have been granted a drug testing exemption ahead of his UFC comeback but he has been tested five times in a fortnight since announcing his return.
Lesnar has faced a blitz from USADA since the news became public two weeks ago, the anti-doping body's athlete database reveals.
The five tests come in the wake of controversy, after the UFC waived its usual policy that athletes coming out of retirement give USADA four months' notice before fighting. Lesnar, 38, has not fought in the UFC since a loss to Alistair Overeem in 2011.
UFC vice president of health and performance Jeff Novitzky told MMA Fighting that Lesnar was likely to face an ongoing testing blitz leading into the 200 promotion on July 9 (US time).
Contrary to popular belief, Lesnar is also drug tested multiple times per year in the WWE.
Lesnar will face New Zealand-born, Australia-based heavyweight slugger Mark Hunt in his return bout. Hunt, 42, was upset by Lesnar's exemption.
"I don't think that's fair. I think it's load of bulls**t, I think it's rubbish," Hunt told Fox Sports Australia in an exclusive interview.
"I don't think anyone should be exempt from testing. If they're trying to clean the sport up - mixed martial arts - this is a bad way to do it. I don't care who you are. It's ridiculous.
"I don't think it's a great move. I think he's juiced to the gills - and I still think I'm going to knock him out."
