The referees working promoter Don King's boxing card at Treasure Island Hotel & Casino in Las Vegas on Saturday night will be able to utilize instant replay for the first time if necessary.
"This will be the first one," said Keith Kizer, executive director of the Nevada State Athletic Commission. "The regulation became official on Tuesday. Of all of our regulatory changes, the most newsworthy thing is instant replay. This will be the first boxing card in Nevada where the referees can use instant replay."
In August, the Nevada commission, the most authoritative in the United States, adopted some rules changes, one of which was a 5-0 vote approving the use of limited instant replay for boxing and mixed martial arts bouts.
However, it took until this week for the change to be formally approved by Nevada's Legislative Counsel Bureau and officially added to the commission rulebook.
Bantamweight titlist Joseph Agbeko defends his belt against mandatory challenger Yonnhy Perez in the main event and Antonio DeMarco faces Jose Alfaro for a vacant interim lightweight title in the Showtime-televised co-feature, although every bout on the card is eligible for replay use.
Kizer said replay use is "completely at the discretion of the referee. The corners and promoters can yell all they want, but nobody can make the referee use replay. It's up to him."
When the referee can use replay is also limited in scope.
"It can only be used to review something when a fight is stopped due to an injury," Kizer said. "They can only use it to review what caused that fight-ending injury. If you do see replay used, it will probably be either to determine if a clash of heads or a punch caused the end of the fight. There are times when we'll see a big cut open up and a fight is immediately stopped. The referee can use replay to determine if it was caused by a butt or a punch."
The other likely scenario in which replay could be employed would be if a punch caused the end of a fight but it was unclear if the punch landed before or after the bell.
Kizer pointed out that if a fighter was cut early in a round, after which the referee makes an immediate ruling on how it happened, and that injury forced the bout to be stopped later in the round or even a few rounds later, it could not be reviewed.
"It has to be immediate," Kizer said.
Replay also will not be used to determine if a knockdown was caused by a punch or was a slip.
If there is no definitive video evidence showing what caused a fight-ending injury, the referee's original call will stand, just like when a referee makes a call in the NFL.
"If the instant replay is unclear, the play stands and you're in no worse shape than you were without having it," Kizer said. "It can only be a positive thing."
Promoter Gary Shaw, who is co-promoting Saturday's card, likes the idea of using replay but has some reservations about Nevada's rule.
"I'm very concerned about using the replay because of the fact that it's only a fight-ending replay that can be reviewed and the only person that has the authority to review it is the referee himself," Shaw said. "If the commission had the authority to ask for the replay I'd be more comfortable or if one of the other referees watching the fight could say to the referee, 'You need to look at that replay.' But what referee in the heat of battle is going to have second thoughts and look to overturn his own call?"
Kizer said the referees in Nevada are comfortable with the process. Robert Byrd, who will work the Agbeko-Perez bout, and Joe Cortez, who will officiate DeMarco-Alfaro, are among the most experienced referees in the world.
"Since the commission passed the regulation, we talked to the referees," Kizer said. "They know this is to give them an additional tool to get the call right. The feedback we've gotten from our officials has been positive. They understand that nobody is trying to second-guess anyone."
Kizer said most boxing events in Nevada are either televised or taped for the promoter.
"I'm hoping that it will be a rarity where there is no footage to look at if we need to," Kizer said. "If there is a card with no replay ability, you are in no worse shape then if the regulation didn't exist."
He said the commission is working with Showtime and Treasure Island to determine the easiest way to logistically handle the need for a replay.
At larger venues, such as the MGM Grand Garden Arena or the Mandalay Bay Events Center, Kizer said using replay could be as simple as the referee looking up to one of the big screens and viewing the replay there.
"But hopefully, we'll work things out so we have a monitor at ringside," he said.
Dan Rafael is ESPN.com's boxing writer.