Max Kellerman, who works for HBO Sports and ESPN, is giving UFC superstar Conor McGregor a zero shot to defeat five division champion Floyd Mayweather Jr.

McGregor makes his professional boxing debut against Mayweather on August 26th at the T-Mobile Arena in Las Vegas.

Mayweather, 40 years old, is coming back from a two year retirement. He walked away from the sport in September 2015.

The contest takes place at the junior middleweight limit of 154-pounds, with 10-ounce gloves being used. Tomorrow there will be a ruling, by the Nevada State Athletic Commission, on whether or not 8-ounce gloves can be used.

McGregor is predicting a knockout victory in four rounds. Kellerman not only finds that scenario impossible, he finds it impossible to picture any scenario where McGregor will win.

Forget inactivity, forget age - Kellerman would give McGregor a zero shot to beat even a 60 year old version of Mayweather.

"They’re in a boxing ring. Conor has a zero percent chance. Precisely zero percent. They’re in a boxing ring. Conor McGregor, there’s no universe in which he can win," Kellerman told Desus & Mero.

"I mean, even the thought of it - if Conor McGregor was like a decorated amateur and they built him up, you know? He had a four-round fight, a six-round fight, this...then after fifteen fights he was like 14-1, and then fought a contender - even if he lost to the contender, right? But at least he held his own over ten rounds, it usually takes about 5 or 6 years to build a guy like that out of the amateurs."

"Then he would have a chance to win a round against someone half as good as Floyd Mayweather. But you’re gonna turn pro after not being in a boxing ring competitively for how many years? And fight one of the best pure boxers of all time? It doesn’t matter that he’s 40 or whatever. If [Mayweather] was 60 it wouldn’t matter."

However, Kellerman could see McGregor lasting the full twelve round distance - if he decides to play it safe in the ring. 

"It depends on how many risks Conor wants to take. If Conor takes risks, he gets knocked out. If he plays it safe he goes the distance," Kellerman said.