The Irishman has been warned that he will have to pay a significant fee if he gets disqualified for kicking or throwing the American to the floor.
Conor McGregor, 29, is making his professional debut and has been accused of “illegal shots” in sparring by Paulie Malignaggi.
But the fine will only occur if he gets disqualified from the fight at the T-Mobile Arena for a deliberate MMA move.
The UFC champion will not get fined if he is disqualified for boxing fouls such as rabbit punching, low blows or pushing his opponent’s head down.
Sources close to the fight refused to reveal the exact amount McGregor will be fined but it is understood to be a flat fee rather than a percentage of his purse with the Dubliner set to earn £70million.
The promoters are confident the size of the fine is substantial enough to ensure McGregor does not consider sabotaging the bout if it is going against him.
The fine suggests that there were fears McGregor would perform such a move despite it being a licensed boxing match.
The Nevada State Athletic Commission insisted McGregor employed a professional referee to oversee his sparring sessions in the build-up to the fight.
They hope that will ensure he is fully aware of the rules of the sport on his debut in the ring.
A controversial ending would leave fans furious with ticket prices eye-watering and pay-per-view costing close to £78 in the US.
Showtime are starting to worry that this event will not break the pay-per-view record in the US which could hit both fighters’ purses.
They remain confident it will easily surpass three million buys but reaching the 4.6m that bought Mayweather’s clash against Manny Pacquiao will be a challenge.
This is a new event for them and they are unsure of the buying patterns of UFC fans, which could ensure the record is still broken if they buy late and on other platforms.
The promoters believe the venue will be 90 per cent full on the night and the pricing of the tickets will still ensure the £57m gate record for boxing will be broken.
Floyd Mayweather is hoping to earn in excess of £200m before quitting the ring for good.