UFC: Adesanya rival Paulo Costa threatens withdrawal over YouTube sensation Logan Paul's windfall

UFC boss Dana White has no sympathy for middleweight contender Paulo Costa, who has pulled out of his scheduled August fight, because he says he won't be paid enough.

Ranked No. 2 to Kiwi star Israel Adesanya, Costa won't fight No. 4 Jared Cannonier at the contracted rate, given what YouTube sensation Logan Paul earned in an exhibition against retired boxer Floyd Mayweather last weekend.

While the payouts aren't yet known, Paul could make as much as US$20 million (NZ$28m), with Mayweather's bank account adding at least US$50 million (NZ$69.5m), TMZ reports.

So White is moving on from Costa (13-1), who lost his most recent fight to Adesanya (20-1) by technical knockout last September at UFC 253. Kelvin Gastelum will replace Costa against Cannonier.

"He's under contract," White tells TSN. "I'm supposed to let people out of their contract just because they're mad that YouTube kid is fighting and making money?

"You should be happy for the kid, good for him. He put himself in a position where he was able to fight Floyd Mayweather and make a bunch of money.

"You're mad? You just came off a ridiculous, horrible performance.

"Come back and put yourself in a position to do something big."

How much Costa was to be paid for the upcoming fight is unknown, but he teased a number on Twitter and contended he never signed a deal for the fight.

"Less than $350k is a joke," he tweets. "UFC needs to pay me as main fighter to have fighting in main events.

"Youtubers are showing all disgrace on this business. Just to be clear, I never signed or locked up that contract.

"Why UFC announced this fight if didn't signed? My question too."

Costa is under contract, however, to UFC for an unknown number of future fights. If he wants to leave the circuit, then the 30-year-old Brazilian should get back to fighting and fulfill his commitment, White told TSN.

"You signed a contract, you're under contract," White says. "If that's the way you feel, you know what I say all the time, we have fights every weekend.

"If you want to be busy, you can fight every weekend if you want to. Get out of your contract and go do whatever you want to do."