LAS VEGAS — The third man in the ring on Saturday night has been in more big fights than Floyd Mayweather Jr. and Manny Pacquiao put together.

The three judges for the richest bout in boxing history also have made hundreds of big decisions during lengthy careers at ringside.

The Nevada Athletic Commission went with proven veterans when it assigned these four men to the highest-profile show in several years in boxing’s capital city.

Kenny Bayless is the most respected referee in boxing, with two decades of title fight experience and a reputation for fairness.

The bout will be judged by three prominent names as well: Dave Moretti, Glenn Feldman and Burt Clements have all been in the business for more than 20 years, and none has a consistent history of head-scratching decisions.

Some fans and commentators have suggested Bayless’ style could favor Mayweather. And Clements once made a scoring error that cost Pacquiao a decision.

But Pacquiao trainer Freddie Roach is confident the officials won’t be the story at the MGM Grand Garden.

“I think we have a great referee,” Roach said. “I think we have some good judges, people that I’m familiar with my whole life. I think they’ll give us a fair call, and I trust this will happen.”

Bayless has been refereeing professional bouts in Las Vegas since 1991, rising to a long-held place among the sport’s top referees. Even in a profession that makes anyone ripe for constant second-guessing, the 64-year-old grandfather with a master’s degree in education administration from UNLV has far more admirers than detractors among fighters and trainers.

“When he was learning to be a ref, I used to let him around my young fighters,” Roach said. “He’s always been fair to me, and I expect a fair fight. I thought he was the best referee for the job.”

Bayless was in the ring for the two biggest pay-per-view cards in boxing before this bout, officiating Mayweather’s win over Oscar De La Hoya in 2007 and his victory over Canelo Alvarez in 2013. He has officiated five of Mayweather’s previous fights and seven featuring Pacquiao, who has shrugged off numerous questions about the choice in the last few days.

If Bayless has any influence on the fight, it might be in his eagerness to keep it clean.

Bayless officiated Mayweather’s rematch with Marcos Maidana late last year, and some fans and commentators thought the referee stepped in too aggressively when Maidana attempted to hit Mayweather from close range.

Maidana couldn’t fight on the inside as he did in their closer-than-expected first fight. Mayweather won the rematch comfortably while Bayless repeatedly broke their clinches — sometimes an instant before they began.

Pacquiao and Roach plan to throw a heavy volume of punches at Mayweather in hopes of connecting with enough of those shots to win rounds. Bayless theoretically could stop the Filipino fighter before he lands extra punches.

Yet Roach and Pacquiao have given no public credence to that theory. Pacquiao usually doesn’t like clutching and grabbing, and he uses unorthodox angles for his combinations.

“We have a good referee, so don’t worry about it,” Pacquiao said. “We focus on the fight.”

Roach also expressed confidence in Bayless’ ability to detect dangerous elbows thrown by Mayweather, whose shifty defensive style sometimes leaves opponents’ faces in contact with his elbows.

“We will have a discussion with the referee about elbows and shoulders,” Roach said. “I know (Mayweather) likes to use them.”

The judges are more likely to decide a bout between two fighters with little recent history of knockouts. Mayweather has stopped only two of his 12 opponents since November 2005, while Pacquiao hasn’t stopped anybody since November 2009.

The 70-year-old Moretti has worked six of Pacquiao’s fights and nine featuring Mayweather, including his rematch with Maidana last year. Feldman hasn’t judged a bout involving either fighter since 1998.

Clements has worked just one of Pacquiao’s fights, but he had an impact on it: The Reno-based judge acknowledges he erred in giving a 10-7 score to the first round of Pacquiao’s first bout with Juan Manuel Marquez in 2004, which was a draw.

If Clements had scored it 10-6, Pacquiao would have received a split-decision victory.

While the foursome’s jobs are tough, they’re also lucrative: Bayless will make $25,000, while the three judges will be paid $20,000.

“When you do fights in Vegas, the fight capital of the world, there’s always pressure on officials,” said Bob Bennett, the NAC’s executive director. “In Vegas, it’s a venue unlike any other. You add to that this epic fight, it becomes more pressurized for some people. It’s incumbent upon me to pick officials who embrace this opportunity.”