Voices from the boxing world are expressing discontent that bringing MMA fighter Conor McGregor into the ring distracts from the sport. (John Locher/Associated Press)

Mike Tyson has said that Conor McGregor is “going to get killed boxing.” Promoter Lou DiBella likened it to a novelty act — “like when Evel Knievel tried to jump the Snake River Canyon.” And Oscar De La Hoya, the former boxing champion turned fight promoter, ominously warned, “Our sport might not ever recover.”

Needless to say, the boxing world hasn’t shown much enthusiasm for Saturday’s fight between the UFC superstar and Floyd Mayweather, the undefeated boxer who came out of retirement for one final mega-payday. To them, the pay-per-view showdown only detracts from advances the sport has made recently and steals the spotlight from fights and fighters that are more deserving.

“You got to take Mayweather and McGregor for what it is: a spectacle. I don’t consider it part of boxing,” said Top Rank’s Bob Arum, who has been promoting fights for a half-century. “It’ll probably do well on pay-per-view, but knowledgeable fight people realize that it is not a true boxing contest.”

McGregor has heard the criticisms and is well aware that boxing literati already have counted him out. He says some corners of the boxing world are simply incapable of imagining an MMA fighter, regardless of his experience or talent, upsetting a boxing legend.

Bob Arum said Floyd Mayweather Jr. is the “finest defensive fighter of our era.” (John Gurzinski/AFP/Getty Images)

“They have a closed mind to how things can be done,” he said. “It’s a set way, and there’s no other way. If that was the case, we never would have reached across the waters in search of other land or we never would’ve went to space. . . . So when I hear the way they carry on and their disregard and disrespect, it is what it is, but I use it as motivation.”

Fight fans are constantly checking the pulse of their sport and recently have felt plenty of reason for optimism. There have been intriguing fights on ESPN (Manny Pacquiao vs. Jeff Horn) and big bouts between talented fighters (Keith Thurman vs. Danny Garcia). And while the sporting world might focus this week on Mayweather and McGregor, the biggest matchup of the year is less than a month away: Canelo Alvarez against Gennady Golovkin.

“Obviously, we have the real fight,” said De La Hoya, whose Golden Boy Promotions is staging that Sept. 16 showdown in Las Vegas. “We have a serious fight. This is a serious fight, a serious event. Two of the best fighters fighting each other. And I think that the fans have recognized that.”

Boxing is a sport fueled by self-interests, but De La Hoya has said he wouldn’t be complaining if Mayweather came out of retirement to face a formidable boxer, Thurman, for example, or Errol Spence. But he feels Saturday’s show does nothing to help the overall health of the sport — only the health of the two fighters’ bank accounts.

“After this fight, neither of them will need us anymore,” De La Hoya wrote in a Facebook post. “Floyd will go back to retirement — presumably for good this time with another nine-figure paycheck — and Conor will go back to the UFC. It’s a win-win for them. It’s a lose-lose for us. We’ll be $100 lighter and we will have squandered another opportunity to bring boxing back to its rightful place as the sport of kings.”

Not surprisingly, the principles in this weekend’s fight bristle at such criticism. They realize hardcore boxing fans and journalists — and many from MMA circles, too — might not appreciate the novelty of a boxing champion fighting a UFC star. But Leonard Ellerbe, the CEO of Mayweather Promotions, points out this fight isn’t really for them.

“How you going to [rip] on somebody’s fight? Something that everybody wants to see?” he says. “We didn’t ask for this. We didn’t sit around and beg for this. The fans want to see this.”

He knows the target audience for this weekend is likely a large swath of casual sports fans, and he expects that audience to produce a record number of pay-per-view buys. One problem, he sees, is the traditional boxing world is relying on old formulas focused on the margins, and it tends to get haughty at a nontraditional matchup.

“You can’t get mad at us because we figured this [stuff] out,” Ellerbe says, “and we’ve done things the right way. . . . You can’t get mad because the people are receptive to it and they embrace it.

“Times have changed. You’ve got to get away from the way things were done before. The traditional — nobody wants to see that [stuff]. Nobody wants to see that.”

One common concern is that $100 spent on this weekend’s show is $100 that’s not being spent on some other boxing pay-per-view. Mayweather was roundly criticized for a boring win over Pacquiao two years ago, and some in boxing circles feel a one-sided, lackluster bout featuring a fighter who has never boxed professionally does nothing to elevate and showcase the sport to the masses.

“If McGregor had fought a preliminary fight or a contender before he went in the ring against Mayweather, who’s the finest defensive fighter of our era, then I would maybe feel different,” Arum said. “But McGregor is a neophyte, and it’s ludicrous for a neophyte to be fighting an experienced and competent guy like Mayweather. It’s a farce. Now if people want to buy a farce and buy a spectacle, that’s on them and not on the sport of boxing.”

Ellerbe seems to think comparing Mayweather-McGregor with any other boxing matchup is a mistake. The interest and demand is unlike anything Mayweather has seen before, he says, including the much-hyped Pacquiao showdown in May 2015. “It’s a whole different feel,” he says.

Whether the serious scribes and hardcore fans tune in or not, Ellerbe thinks the showdown is bigger than boxing. The fact that two fighters from different disciplines are even entering the ring speaks to some larger fascination the American public has with celebrity and popular culture. Sports aren’t just another form of reality television programming. Reality TV is also sport.

“It’s called entertainment. At the end of the day, we’re in a society now where that’s what people want to see,” Ellerbe says. “You can sit there and say whatever you want to. But people are intrigued by the Kardashians. That’s the way it is. How can you be mad at anybody for that?

“At the end of the day, this is entertainment, and we’re giving the fans exactly what they want to see.”