This weekend in Anaheim, California, between 15,000 and 18,000 fight fans are likely to gather to watch boxing.

Sure, they will get the interesting super middleweight fight between Daniel Jacobs and Shane Mosley Jr. and the remainder of the undercard, but the commercial needle-movers are two former UFC stars Nate Diaz and Jorge Masvidal.

Despite limited boxing experience – Diaz is 0-1, having lost a 10-rounder to Jake Paul, and Masvidal is 1-0, having won a majority decision in a four-rounder back in June 2006 – their fame and shared rivalry has led to the latest in an increasingly long list of financially viable crossover fights.

Solomon Engel, Fanmio CEO, has put the Honda Center bill together and admitted of the show: “It’s never easy. We’ve done this before, but there’s always a stress element to it, of course, with athletes. But it’s going very, very well.”

Engel has the boxing promotional rights to Masvidal, and he hopes that victory over Diaz will springboard another big fight night for the MMA icon later in the year.

“We have a multi-fight deal with Masvidal for boxing,” Engel added. “And we already have his next fight lined up – it’s almost done, and it’s something a lot of people will talk about. 

“He’s not fighting a crossover fight, he’s fighting a very well-known, famous boxer for his next fight. He has to come through on Saturday night.”

But the story of Masvidal-Diaz reaches outside of boxing. Purists will focus on Jacobs-Mosley, but the backstory and history of the MMA stars will attract fans who normally wouldn’t watch boxing. Engel sees that, too.

“We did a deal with Masvidal and the UFC to sign Masvidal exclusively for boxing,” he explained. “We’re focused on boxing; it’s a big part of our business and focus. So we knew Masvidal was looking to box professionally, and we thought it was a good opportunity for us to try to work with him. Masvidal is one of the better boxers in the UFC. Notoriously, throughout his career, he had a good stand-up and he has a small history of professional boxing. He’s always been a very skilled boxer. We thought, for all those reasons, he’d be great to work with. And he has been.

“As far as Nate Diaz, these two guys have history – they fought many years ago, sold out Madison Square Garden, very high number of pay-per-views were sold to that event. We thought this was a great opportunity to bring these two guys back together.

“If you recall, it was the BMF belt [in the UFC], the first belt, and it was a controversial stoppage [a Masvidal win], so with that there’s a great story behind it. These guys wanted to rematch for a long time, weren’t able to get that put together, so here we are, brought back together and they’re going to fight again – just this time it’s boxing, because at the end of the day, it was in both of their ambitions to box.”

And Engel insists the fighters deserve their respect, for fighting and for the work they’ve put in. It might be a crossover fight, but Engel has high hopes for the night.

“These guys are training boxing, Diaz and Masvidal,” Engel said. “They’re very serious in camp and they’re going to come out, and I think Masvidal looks fantastic. We’ll see how he looks under the spotlight. And as for Diaz, the world had a chance to see it against Jake Paul, but I don’t think he took that fight as serious as he’s taking this one. He’s very deeply integrated into his camp. This is a real boxing match. While we know they have a separate fanbase, the MMA crowd, we wanted to build out a card that was focused on boxing more than anything, and that’s why we brought in Danny Jacobs and Mosley.”

Which takes the conversation toward the fight that will be heralded as the nominal main event in boxing circles. Jacobs is 37-4 (30 KOs) and has lost two of his last four, while Mosley is 21-4 (12 KOs) but has won his last four.

“Danny Jacobs is a former champion – great, great fighter. He’s ambitious to get back in the ring, he’s been training, he’s been in camp for a long time, just getting ready for it,” Engel said. “Shane Mosley Jr. was on a winning streak. We thought this would be a great opportunity considering where he stands in his career, and if he wins this fight against Jacobs, it’s definitely something that I think would advance him on the boxing scene. We thought the two would be a great matchup.”

There is also a bout between 10-0 lightweight prospect Amado Vargas against 7-0-1 Sean Garcia.

“They’re both undefeated and training really hard – young kids, very ambitious. I think it’s going to be interesting to watch these guys go at it,” Engel concluded. “Sean Garcia is Ryan Garcia’s younger brother, and then you have the Vargas family. Both families are going to be there, and they have this little feud going on between them, and it’s going to be a good fight and a lot of tension between the families and them.”