Ngannou said he was getting dressed in preparation to go to Honda Center in Anaheim, California, on Saturday when his agent, Marquel Martin, told him that the UFC sent Martin an email threatening to sue him.
The UFC's allegation in the email, Ngannou said, was that Martin discussed Ngannou competing in boxing with Nakisa Bidarian, the business partner of Jake Paul, while under UFC contract.
A source with knowledge of the situation confirmed with ESPN the timing and contents of the email. Martin is an agent with Creative Artists Agency (CAA).
"I walked into the room waiting for my manager, my coach," Ngannou said on "The MMA Hour." "And they were like, 'Wow.' I'm like, 'What's going on?' They told me they just received an email from the UFC saying they're going to sue [Martin] for talking with this guy, Nakisa. Yeah. I'm like, 'Who is Nakisa?'"
Bidarian is the former UFC chief financial officer, the current adviser to Paul and the co-founder of Paul's Most Valuable Promotions company. Ngannou said he talks about boxing with a lot of people -- he has said publicly many times it's his dream to box -- but does not know who Bidarian is.
"I wouldn't recognize him if you put him in front of me," Ngannou said.
Bidarian, Martin and the UFC all declined comment on the matter.
Ngannou ended up unifying the UFC heavyweight title with a unanimous decision win over interim champion Ciryl Gane in the main event of UFC 270. UFC president Dana White went against custom and did not wrap the belt around Ngannou's waist, and surprisingly did not come to the postfight news conference.
The UFC and Ngannou have been at odds over Ngannou's contract for months. Had Ngannou lost, his contract would have expired and he would have been a free agent. Because he won to retain the UFC heavyweight title, the promoter's "champions clause" kicks in, meaning Ngannou remains under contract for one more year or three fights, whichever comes earlier.
Ngannou has said that he is willing to hold out for an entire year rather than compete again on this contract, which he said Monday pays him only $600,000 per fight. The root of Ngannou's issue with the UFC, he said, is not completely financial. He said on "The MMA Hour" that he turned down about $7 million over the past two fights, because accepting that deal would have meant tacking on more fights to his contract, which he was not willing to do under the circumstances.
Ngannou said he would like to stay with the UFC but also compete in boxing while doing so, something, that except for Conor McGregor's boxing match against Floyd Mayweather, the promotion has never let its athletes do. Ngannou said it's a question of "freedom" as an independent contractor, which UFC fighters are legally classified as.
"The term of the contract, everything that they put into [it], they hold you like in captivity," Ngannou said. "You can't do anything, you have no rights. The contract is one-sided. ... You don't even have health insurance while you're doing this, putting your body on the line to put on the show. Risking everything."
Ngannou, 35, said he understands the lack of health insurance as an independent contractor, "but treat me as such then," he said.
"You can be free and fight for the UFC," Ngannou said. "I just want to be free. We are supposedly independent contractors. [An] independent contractor is technically a free person. That's the reason why they need some adjustments in that contract. That's what I've been fighting for."
Ngannou came into the Gane fight with a torn right MCL and damaged ACL, he said Saturday night. He will need surgery, so he is likely looking at extended time off. Ngannou still said he would like to fight again this year despite the injury and contract situation.
The future for the world's top heavyweight MMA fighter is very much in flux, though.
Ngannou said he didn't gain any more clarity after beating Gane. No one from the UFC has approached him or Martin to discuss a new contract, Ngannou said.
"It doesn't look like they want to talk to me anymore," Ngannou said.