Eddie Hearn has claimed Conor McGregor is bigger than the UFC and has branded the situation a "nightmare" for the promotion.
The Irish star is currently sidelined from competing in the octagon after suffering a broken leg in defeat by Dustin Poirier last year.
He is considered arguably the sport's biggest superstar having been involved in eight of the top ten selling pay-per-view events in the promotion's history.
Hearn believes that McGregor must have caused "disruption" to the UFC's model during his illustrious career.
“For UFC, where they’ve been very smart is by – it’s such an honour to get a UFC deal," Hearn told the MMA Hour.
"You see these kids coming out of Bellator, or Cage Warriors, or wherever it is; but the thought of getting a UFC contract is everything. But I feel in the UFC, they don’t want you to get too big.
"And when you do – and I used to almost laugh at Conor, because I could just imagine just the disruption that he was causing in that organisation, because that’s not really the name of the game.
"We don’t want a star that is bigger than the UFC. Conor McGregor became bigger than the UFC. Really. And that’s a nightmare for those guys.”
McGregor is considered the poster boy of UFC in the modern era, and has generated huge earnings both inside and outside the cage.
Despite suffering back-to-back defeats last year, McGregor earned over £36million last year from his duels with Poirier.
This is a significant gap compared to many of the other champion's in the promotion including Ngannou who earned just $600,000 for his recent title defence against Cyril Gane.
McGregor is expected to continue to headline events despite having slid down the lightweight rankings after consecutive losses.
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He demanded an immediate title shot which looked likely to be accepted by Oliveira who claimed he was "waiting" for his official challenge.
However this has now been written off for now with Oliveira booked to defend his title against Justin Gaethje.
A high-profile option could be for McGregor to stage a trilogy with Nate Diaz who is in the final fight of his UFC contract.
UFC president Dana White has explained that his desire to face anyone in any weight category including Diaz allows him to be given "special treatment".
"Yeah, that’s true and not true," White replied to Daniel Cormier. "If you look right now at the rankings, Conor McGregor is ranked No. 9 in the world [at lightweight].
"So, who the hell knows what this thing’s going to look like by the time he comes back? So, I couldn’t honestly answer that question. I’ve said it publicly a million times, Conor McGregor, literally, would fight anybody. I’m telling you.
"Conor McGregor has been that guy since the day he walked into this f****** company. So, for anybody to point the finger and say, ‘Oh, this guy’s getting special treatment.’ This guy is special. This guy’s f****** special."
