By Radio Rahim

Top Rank's CEO Bob Arum believes the UFC is the only obstacle in the way of the much hype cross-sports showdown between former five division world champion Floyd Mayweather Jr. and UFC superstar Conor McGregor.

McGregor gave Arum a big assist last week, when he took part in the festivities of Michael Conlan's pro debut at Madison Square Garden in New York City.

Both Mayweather and McGregor are ready to do the fight. 40-year-old Mayweather, who retired from boxing in September 2015, announced that he was coming back to the ring - but only for a Mcgregor fight. The big issue is overcoming McGregor's exclusive contract with the UFC.

In a recent interview, UFC President Dana White stated that he wouldn't stand in the way of a potential Mayweather-McGregor pay-per-view. He wants to see McGregor make a major payday, even if doesn't make much business sense for the UFC.

Arum doubts the words of White. He says the UFC is playing hardball with the financial terms for the contest, with a clear demand for a very sizable take of McGregor's money from the event.

"I think the only impediment there is the UFC, because UFC doesn't treat fighters the same way that boxing promoters do. In other words, UFC fighters get so much less than boxers do. They proposed a deal to Conor that on his share of the purse - they take 50 percent. Now give me a break," Arum said.

"If the fight doesn't happen, not that I think it's going to be a great fight, because I think Conor fighting Mayweather is not really a fight if it's boxing. Conor is a great MMA fighter, but hasn't shown anything in boxing. And Mayweather's one of the great fighters. But if that fight doesn't happen - the blame will only be on the UFC."