After Conor McGregor earned a guaranteed $30 million to step into a boxing ring against Floyd Mayweather on Saturday (and potentially upwards of $100 million once pay-per-view receipts are counted), it's likely UFC will need to loosen its purse strings in order to get him back into the Octagon. 

The UFC may have to end up doing the same for McGregor's best available big-money opponent, too, according to Richard Perez, the boxing coach of Nate Diaz. 

"At least $20 million, $30 million," Perez told Submission Radio on Thursday. "Come on. UFC's making a whole lot of money, a whole lot of money and they're pocketing it. They're giving more to McGregor, so it's not fair because it takes two in that ring to draw a crowd -- I mean, a good two fighters.

"It's just like Mayweather when he fought [Andre] Berto [in 2015]. It was not even sold out at all. It was embarrassing. It's because that guy couldn't draw a crowd. See, that's what I'm saying, it's the fighters that draw the crowd, and Nathan and McGregor, the third one would be outstanding. Everyone knows that. So he needs to get paid at least $30 million easy."

Diaz, 32, hasn't fought since losing to McGregor last August in their high-profile UFC 202 rematch (which set a new UFC PPV record at 1.65 million buys) and has repeatedly shot down requests to return unless the fight offered is a trilogy with McGregor. 

A third McGregor-Diaz fight likely offers UFC its most profitable PPV option this calendar year and would likely come on Dec. 30 at UFC 219 if recent comments by president Dana White mean anything. But UFC will likely have a numbers game on its hands when it comes to fight purses now that McGregor earned more money in one night against Mayweather than he has his entire UFC career. 

McGregor's previous high was the disclosed $3 million -- a UFC record -- he earned in the Diaz rematch (although he reportedly made upwards of $10 million more after PPV bonuses). Diaz, meanwhile, made a combined disclosed amount of $2.6 million for his two 2016 bouts against McGregor, which included Diaz's submission win in their first meeting at UFC 196. 

The 10th-round TKO loss for McGregor, 29, against the 40-year-old Mayweather on Saturday, doesn't appear like it will hurt the brash Irishman's future drawing potential considering he overachieved against the best boxer of this era. 

Perez said he wasn't surprised with McGregor's performance but believed that Mayweather, who was fresh off a two-year retirement, wasn't completely himself. 

"McGregor was kind of awkward for Mayweather," Perez said. "So Mayweather, he said he was gonna come out toe to toe with him, but he didn't. And I thought McGregor did good for the first four rounds but then he started to slow down a little. He threw some good shots in there. 

"If Mayweather was fighting the top five right now, I don't think he'd make it through because of the way he looked that day -- unless he wasn't serious. It seemed like he was but McGregor, he did alright."

Perez also believes McGregor has yet to see the best version of Diaz, who took their first fight on 11 days' notice and entered their rematch with an undisclosed injury. 

"These guys are true warriors, they go out there and still fight [despite injury]," Perez said. "So as far as McGregor coming out in the cage if he fights Nathan and Nathan gets in shape, it should be a good fight, a great fight, because Nathan can move and he's got great footwork and he can throw a lot of combinations and make McGregor miss, counter off of it, use his reach."

Congrats to the champ last nite 50-0 💯💯

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Diaz made an appearance at Mayweather-McGregor in Las Vegas and greeted the former pound-for-pound boxing king in his locker room afterwards.