Manny Pacquiao's hopes of facing Conor McGregor instead of Floyd Mayweather Jr in a cross-code boxing match have been thrown into major doubt after Ultimate Fighting Championship (UFC) president Dana White ruled out working with the Filipino's promoter Bob Arum. Talks are ongoing between the Irish mixed martial arts superstar and the unbeaten American boxer yet an agreement has yet to be reached between the pair.

Negotiations cleared a major hurdle last month after McGregor and the UFC reached an agreement over the purse split for the bout. White has now begun discussions with Mayweather and his chief representative Al Haymon ahead of the fight which is expected to take place in 2017.

Dana White
White says a previous falling out with Arum means Pacquiao's hopes of facing McGregor are dead in the water. Getty Images

But with those talks having not yet reached a conclusion, attention has already turned to who could stand in for Mayweather if he withdraws from the bout - with McGregor intent on making his boxing debut having applied for a license in Nevada. Arum has suggested that Pacquiao could be parachuted in to fill the void.

"Be patient and don't give in," Arum said of the UFC's talks with Mayweather's team. "Dana's a good negotiator and he'll get the thing done. But he can't be pushed around by Mayweather and his people.

"Pacquiao's got a tough fight - a really tough fight - against this guy in Australia, Jeff Horn. After that fight on July 1st, if McGregor is still looking for an opponent, Manny Pacquiao is there."

However, White has poured cold water over a prospective fight between Pacquiao and McGregor after suggesting he would never deal with Arum. The 85-year-old has developed Top Rank into one of the leading boxing promotional companies around but having previously referred to UFC fans as "skinhead white guys" White is unwilling to do business with the boxing Hall of Famer.

"Bob Arum and I don't get along," he told TMZ Sports. "If Bob Arum and I had the two last fighters on earth I wouldn't make a fight with that scumbag."