By Rick Reeno

MGM Grand, Las Vegas - According to trainer Freddie Roach, there are no other challenges on the horizon for Manny Pacquiao - except Floyd Mayweather Jr. (42-0, 26KOs). This Saturday at the MGM Grand in Las Vegas, Pacquiao (53-3-2, 38KOs) will defend his WBO welterweight title against Juan Manuel Marquez (53-5-1, 39KOs) in a trilogy fight.

On Monday, Top Rank's CEO Bob Arum, who promotes the Filipino superstar, discussed a number of possible opponents for Pacquiao in the future - but Roach doesn't believe any of them will pose a challenge.

"I don't see anybody. There's nobody out there. I think that Mayweather fight has to happen. It needs to happen because it's the only challenge out there. I don't see any other challenges," Roach said.

Roach's temper was raised when the topic of Team Mayweather's recent announcement came up. The adviser for Mayweather, Leonard Ellerbe, recently disclosed that his boxer was going to return on May 5th, and the MGM Grand was placed on hold. While not revealing Pacquiao's name directly, Ellerbe hinted that Mayweather's main target was the "little fella.' Like Arum, Roach doesn't like idea of Mayweather already selecting a date and venue before the two sides get a chance to sit down and negotiate the actual terms.

"I'm kind of tired of Floyd. Just shut up and fight. We'll fight him any day of the week. Who the f**k is he to make the rules? If that fight doesn't happen, I'm not going to cry," Roach said.