MANILA, Philippines – Top Rank chief executive Bob Arum is not counting out welterweight champion Robert Guerrero against Floyd Mayweather Jr., even though “The Ghost” will likely be a massive underdog against the unbeaten American.

“It’s going to be a fight,” Arum told Ronnie Nathanielsz of Phil Boxing.

“I think Guerrero has a helluva shot. I really believe that,” he stressed.

Mayweather will enter the ring for the first time in over a year against Guerrero on May 4 at the MGM Grand Garden Arena in Las Vegas.

“The Ghost” earned the title shot after an impressive performance against Andre Berto last November 2012, dropping the former champion twice en route to a unanimous decision victory that allowed him to retain the interim World Boxing Council title.

Arum is currently working on putting together a fifth fight between rivals Manny “Pacman” Pacquiao of the Philippines and Juan Manuel Marquez of Mexico.

As for a potential super-fight between Pacquiao and Mayweather, Arum dismissed it, telling Nathanielsz “just forget him (Mayweather).”