Top Rank Promotions CEO Bob Arum believes that the long-proposed showdown between Floyd Mayweather Jr. and Manny Pacquiao might not happen at all.

Arum said in an interview that he doesn't expect Mayweather to accept a showdown against Pacquiao because the reigning pound-for-pound king will make money whoever his opponent will be - not because of his skills, but because of his lucrative deal with Showtime.

"I don't think Mayweather will ever agree to fight Pacquiao, particularly while he has a cushy deal with Showtime. He makes money fighting anybody," Arum said via BoxingScene.

Arum also pointed out that the reigning World Boxing Council welterweight and light middleweight champion, and World Boxing Association welterweight kingpin is afraid to face Pacquiao because the Filipino boxing icon is an excellent southpaw.

"I promoted the guy for ten years and I know how difficult it was to get him in the ring with any southpaw," Arum said. "When you talk about a southpaw who can move like Manny, that's not the kind of opponent that Mayweather feels he would do well against. That's the problem. If Manny agreed to fight right-handed, the fight would be agreed in five minutes."

Arum also played down comparison between the monetary earnings of Pacquiao and Mayweather. The unbeaten champion earned a guaranteed $32 million paycheck for his rematch with Maidana, but Arum pointed out that Pacquiao's earning is bigger when tax is removed from the gross amount.

"You can't believe a word they say. He has a guarantee of $32 million with Showtime and they agreed to increase that to $40 million when he fought Canelo. But his guarantee for the Maidana fight is $32 million. It's still a lot of money, but, remember, in the United States he still has to pay federal income tax to 39.6 per cent," Arum said. Manny makes more than he does by fighting outside the United States at least once a year. Manny's net income after tax is more than Floyd's."

Pacquiao is set to defend his World Boxing Organization welterweight title against Chris Algieri on Nov. 22 in Macau, China. Despite Arum's recent statement, experts are still hoping that a win will finally lead to the super fight between the two boxing superstars.