The August 26 fight is looked at controversially in the boxing world, with a number of fighters feeling like they should've had a shot at Mayweather rather than a man who's never boxed professionally.
The UFC stripped McGregor of his featherweight belt shortly after that fight when he announced he would be taking some time off after he and long-time partner Dee Devlin had their first baby in May.
O'Brien hit McGregor with several questions, mostly asking him to reply to things Mayweather has said about him and what he expects to happen in the fight, all of which McGregor poo-pooed.
"This is a bout that has already been set at a specified weight class", the physician chairperson Raymond Monsell wrote in a letter released on Tuesday. "But 8-ounce gloves, he will be done in two".
"I believe now that the gloves are eight ounces I don't believe he makes it out of the second round", McGregor said on a conference call on Wednesday. Chairman Anthony Marnell did say he was upset that Mayweather and McGregor had used the commission for promotion on social media.
"We've seen a shift in the fitness industry, in that the average consumer is seeking access to the same training that elite athletes have available, and more studios and gyms are now dedicated to a specific discipline", he said in a statement.
Finally, McGregor feels boxing experts have been very dismissive of his chances in the ring and he fully intends to open their eyes. It's light-hearted. I don't take it personal.
Former UFC welterweight title contender Dan Hardy will be part of the upcoming broadcast for Conor McGregor-Floyd Mayweather. And I've been off a couple of years.
The bookies seem to think there will only be one victor, but do you give McGregor a chance?