By Edward Chaykovsky

Unless a mega-fight with Floyd Mayweather Jr. materializes, WBO welterweight champion Manny Pacquiao (57-5-2, 38KOs) is still on course to drop down to 140-pounds in 2015.

Pacquiao has been fighting at 147-pounds against much bigger men since 2008. During that period, he actually went up to 150-pounds to beat Antonio Margarito for the WBC 154-pound title and took one trip down to 140, to beat Ricky Hatton for the IBO title.

The Filipino star has been unable to secure a knockout win since 2009, which his adviser Michael Koncz attributes to his boxer facing much bigger men. Both Koncz and trainer Freddie Roach expect the streak of knockouts to resume at 140.

"What people don't really understand, especially the casual boxing fans, is that we're fighting in a weight class much higher than our natural body weight," said Koncz told GMA News. "So these guys are big, these guys are strong, they are used to the power punches. Anytime we fight in the welterweight division, we're easily giving up 20 to 30 pounds. And that's a big advantage to his opponent."