No matter how you feel about them, fights between professional boxers and mixed martial arts combatants could be here to stay.

What was once thought to be a one-off bout between Floyd Mayweather and Conor McGregor in 2017 made hundreds of millions of dollars. Unsurprisingly, with that kind of dollar figure in play, fighters and promoters are interested in making more of these types of fights.

A lot of fighters on both sides of the aisle have been angling to be the next ones up. Fighters who ply their craft in boxing rings and the Octagon have thrown their names into the mix, for everything from pure boxing and MMA fights to hybrid matchups against cross-sport competitors.

McGregor wants a rematch with Mayweather or a fight with Manny Pacquiao. Terence Crawford wants McGregor in both the Octagon and ring in a two-fight series. Jorge Masvidal wants to face boxing's elite, Canelo Alvarez. UFC heavyweight champ Stipe Miocic and No. 1 contender Francis Ngannou have their eyes on Tyson Fury, and Fury says he's game for it.

play 1:07 McGregor opens up about potentially boxing Pacquiao Conor McGregor says there have been talks to box Manny Pacquiao and proclaims he'll win a boxing world title. Order UFC 246 here on ESPN https://plus.espn.com/ufc/ppv.

The list goes on.

MMA fighters understand the lucrative paydays and worldwide exposure they can get if they are able to get into the boxing ring with a pugilistic great -- figures that dwarf even the biggest published fight purses in the UFC. Boxers have the chance to pocket a big payday and earn crossover exposure -- and, in many cases, the circumstances of most of these proposed fights benefit their side.

Boxing trainer Joe Goossen's attention has been captured by all the MMA vs. boxing talk. He recently sat down with ESPN at his Ten Goose Boxing Gym in Van Nuys, California, to talk about how some of these MMA fighters stack up in terms of boxing ability and how they'd match up if they ever make the walk into the squared circle.

The scouting report on Stipe Miocic

play 1:17 Miocic: I would love to box Fury Stipe Miocic isn't interested right now in a rematch with Daniel Cormier, but he wants to look into a fight with Tyson Fury.

After watching some clips of Miocic, Goossen was impressed with his right hand, but was troubled with the head placement of the 19-3, two-time UFC heavyweight champion.

"In a boxing match, you'd be very concerned as a trainer that your fighter has got his head up that much, coming in with that right hand," Goossen said. "Fighters are taught sometimes when that right hand is thrown at you, you block it and you turn that hook off of it, right away. So a great fighter would know that, and would've understood that right hand was coming, even as he went over it, because he would've been tucked in more.

"Then he would've either clipped off a left hook, or an uppercut, or a counter right hand. In boxing, if you throw that right hand, guys are going to tuck or roll and come back with a right uppercut, or a straight right hand. They're going to counter on the opposite side of your right hand. He would be very vulnerable for a counter right hand, and then vulnerable for a left hook by his chin being up a little bit too much there."

For Goossen, getting Miocic to become a bit more compact in his posture as he throws his punches and getting his chin tucked in would be a key point of emphasis in training.

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During Miocic's 2016 victory over Andrei Arlovski, for example, Goossen felt Miocic failed to display the patience needed in a boxing match. Goossen thought Miocic pressed the action and also found Miocic's balance after throwing strikes to be problematic when trying to avoid counterattacks.

"The right hand was skillful, but he almost rushed the second attack," Goossen said. "He's off-balance a little bit. He brings his right leg all the way over. ... Actually, the left leg drops all the way behind him and he comes in with a real sloppy two, three left hands that didn't land, because he didn't reset his feet in the correct position."

Miocic's 2014 contest with Fabio Maldonado, which lasted all of 35 seconds, showed off what Miocic does well when his boxing is sound.

"[Miocic] backed up with his chin up. That's dangerous," Goossen said. "[But] here's that right hand, good turn on the back foot, and his legs were in the right position -- that's why he dropped the guy. It was really well-placed, his balance was good and his stance was right on target."

Goossen likes Miocic's strength and raw power, and also his willingness to mix it up. But it's clear that he has a lot of rough edges to smooth out in his game before he would be ready to box against a professional.

The scouting report on Francis Ngannou

play 1:12 Francis Ngannou's greatest hits Look back at Francis Ngannou's UFC highlight reel, including ferocious knockouts of Andrei Arlovski, Alistair Overeem and Curtis Blaydes.

Ngannou (14-3) is one of the top-rated heavyweights in the UFC. He aspired years ago to be a boxer before turning his focus to mixed martial arts while he was in France.

"Francis is a baaaad dude. He's a legit heavyweight," Goossen said.

Goossen reviewed a number of Ngannou's bouts and saw a different type of fighter than what he witnessed in Miocic. Goossen saw a more polished puncher with an eye for seizing the right opportunity, starting with Ngannou's own fight against Arlovski in 2017.

"The opponent throws a right hand and you see what Francis did? He tried to counter with a left hook. When that missed, he came back with a right hand, right off the hook," Goossen said. "Then [Arlovski] throws another right hand and Francis counters with a left hook and .... there it is! And [Ngannou] follows up with a right uppercut, because the left hook put him in position for the right uppercut, because [Arlovski]'s trying to duck from it and it put him into the right uppercut. That's done exactly the way it's supposed to be done."

Heavyweight Francis Ngannou, right, lands a perfect left hook on Andrei Arlovski. John Leyba/Getty Images

Goossen had more of the same reaction after viewing Ngannou's second-round stoppage of Luis Henrique in 2015.

"Nice right, uppercut, double left hook," Goossen said of Ngannou's well-placed punch variety. "That was beautiful. Francis there, threw three left hooks and he stepped with each of them. Now here's a left uppercut; he threaded the needle. If he would've come back with a short right hand there, it would've been even worse for Henrique, who is knocked out cold.

"He's following up with everything, he knows how to set up a punch and what he does is follow you -- and not be off-balance."

Then there was the iconic knockout Ngannou scored against Alistair Overeem in December 2017.

"He followed that right hand up with a left uppercut," Goossen said. "Now, it was it wide and wingy? Yes. But he landed it, nevertheless."

Goossen appreciated that with Ngannou, one punch will naturally lead to another.

"I like the fact that he went with the flow of the action," Goossen said. "ln other words, I throw a right hand, now from the action, that takes the flow of your head over to my left side. Now I'm going to be aware of that and then I've got a variety of punches I can work off that."

Could Miocic and Ngannou handle a fight with Tyson Fury?

Tyson Fury, right, displays his defensive moves against Deontay Wilder during their 2018 fight at Staples Center in Los Angeles. Lionel Hahn/Getty Images

"Fury is not an easy guy to hit. Most guys in the top 10 are not easy to hit as boxers," Goossen said. "What I notice about the MMA guys is they will leave themselves exposed a little bit more. But it's mainly because once they get it over on you [with a series of punches], they go at you with reckless abandon because the counterpunching is not as precise [in MMA], if it's even there at all.

"The thing about boxers, what they have over MMA guys, more than anything, is their sense of defense, where their hands and heads are."

Both Miocic and Ngannou are listed at 6-foot-4, while Fury hovers around 6-9. So there would be a decided height and reach advantage to contend with, along with the fact that Fury has an educated left jab and superior ring generalship.

The scouting report on Jorge Masvidal

Jorge Masvidal's punch combination against Michael Chiesa, left, impressed boxing trainer Joe Goossen. Josh Hedges/Getty Images

Of all the footage of the three UFC fighters that Goossen viewed, he was most impressed with Masvidal. It starts with his form.

"I like what I saw on the mitts. He was turning his hands over nice," Goossen said while watching highlights from Masvidal's 2013 fight against Michael Chiesa.

"Look at those combinations -- the right hand, then he went to the liver, that's nice. He kicked ... and then got his distance. Masvidal is putting those [punches] as good as you can when you're that close on the ground and then chokes the guy out," Goossen said. "What I liked was that he has a very good sense of flow with his combinations."

As he viewed a three-round decision against Patrick Healy from 2014, Goossen noted Masvidal's power from all angles.

"You don't want to get kneed or kicked or hit by this dude," Goossen said. "He has a great right hand going backwards [from the southpaw stance]. This guy has got to be at the top of his game.

"Good right hand, he turned it over," Goossen continued. "See, he's always throwing that left hook after he throws that right hand, even if the guy isn't there."

Goossen appreciated the fact that Masvidal layers his punches, just as a boxer would. He then noticed a significant change from Masvidal during his first-round victory over Cezar Ferreira in 2015.

According to boxing trainer Joe Goossen, UFC welterweight Jorge Masvidal, left, "got it all." Pat Scaasi/Getty Images

"He came into the right-handed stance, into a left-handed stance, at the very end," Goossen noted, referring to "shifting," where a fighter will go from an orthodox position into a southpaw stance (or vice versa) in a seamless transition during an exchange of punches.

"Does this guy do this to everybody? He's something else, let me tell you. He keeps his hands up real well, very athletic, great body attack, he knows what he's doing," Goossen continued while watching Masvidal's fight against Donald Cerrone. "He must be working with somebody in the boxing field."

Finally, Goossen watched Masvidal's second-round stoppage against Darren Till, which earned him Performance of the Night and Fight of the Night bonuses.

"See that left hand, right off the right hand? [Masvidal] waves him in, and then he goes southpaw," Goossen said. "Man, I tell you, this guy is dangerous, right-handed or left-handed, he's on top of you. I want to get a good look at him, because if I ever run into him at a bar, I'll be nothing but polite."

To his eyes, Masvidal -- regardless of fighting genre -- is the prototype of who he would like to train.

"I would've loved to have had an aggressive ass-kicker like that in my stable as a fighter, because he looks like he can do anything: spinning kicks, flying kicks, elbows, you name it, southpaw, right-handed, combinations, accurate and a vicious punch," Goossen said. "This guy's got it all."

How would Masvidal fare against Canelo?

play 1:49 Masvidal 'dead serious' about boxing Canelo Jorge Masvidal tells Ariel Helwani that he's serious about his desire to box Canelo Alvarez and explains why he'll cause issues for Alvarez.

Masvidal has brought up the idea of facing Alvarez when suggesting a step into boxing. Goossen, effusive in his praise of the UFC's BMF, feels like with the right kind of preparation, Masvidal could do some real damage in boxing.

"Let me tell you something: If there is one guy that could maybe come out of nowhere -- and when I say 'nowhere,' I mean from outside the boxing community, from another realm of combat sports -- it would be this guy. I'm more than impressed with him," Goossen said. "This guy's a killer."

Goossen believes that anyone making the transition to boxing would need three or four development fights, while staying in the gym for a good year-and-a-half to two years, to polish up their pugilistic skills. But the veteran trainer believes that Masvidal already has a solid foundation in place and would adapt relatively quickly.

"That's not far-fetched," Goossen said, summing up how he feels Masvidal would fare against Alvarez with that kind of prep. "Look, would [Masvidal] be favored? No, but let me tell you something: He'd make a great account of himself. There's no way this guy gets blown out by any combat expert.

"Remember something: He throws his fists, too, for a living. Canelo's just lucky that this guy can't kick him."

It's clear that through these highlights Masvidal has earned a fan in Goossen. So will Goossen be buying Masvidal's next pay-per-view? That's a yes.

"Tune in? I'd like to train him," he said.