LAS VEGAS -- The Manny Pacquiao whom so many fight fans fell in love with was a whirlwind who attacked opponents with nonstop aggression, firing punches with abandon.

That's the Pacquiao who annihilated Oscar De La Hoya and sent him into retirement after a fight in which Pacquiao was moving up two weight classes for and was the heavy underdog.

That's the Pacquiao who starched Ricky Hatton with one punch in the second round. And that's the Pacquiao who beat and battered Miguel Cotto into submission in a 12th-round knockout in 2009. That's also the last time that Pacquiao, boxing's only eight-division titleholder, scored a knockout. So where is that ferocious Pacquiao now? We haven't seen him in ages.

In 2010, the Filipino icon appeared to carry Antonio Margarito over the final few rounds of a one-sided decision win, letting up and showing compassion rather than continuing to deal him a wicked beating. When Pacquiao easily outpointed Shane Mosley in 2011, he knocked Mosley down in the third round and never tried to finish him. Pacquiao seemed more interested in tapping gloves with Mosley every round out of respect than destroying the faded former champion.

Fast-forward to November, when Pacquiao returned from a year layoff following a knockout loss to rival Juan Manuel Marquez in their fourth fight to face Brandon Rios. Even though Pacquiao dominated Rios, he appeared tentative, perhaps still spooked by the knockout loss to Marquez. But perhaps the fire that once burned deep inside Pacquiao has been extinguished and that the fighter so many fell in love with because of his pedal-to-the-metal style no longer exists.

That is certainly the opinion of welterweight titleholder Timothy Bradley Jr., who has spent much of the buildup to his rematch with Pacquiao on Saturday night (HBO PPV, 9 ET) at the MGM Grand Garden Arena insisting that Pacquiao has grown soft, is no longer hungry and no longer possesses the killer instinct that helped make him a global star.

Not so, Pacquiao said.

"My motivation is the same now as it was when I started my boxing career," he said. "I love the competition, and I love to win. When that stops, so does my professional boxing career. But I don't see that happening for a long time."

But a couple of months ago, Bradley (31-0, 12 KOs), of Palm Springs, Calif., challenged Pacquiao on that. He sat directly across a table from Pacquiao (55-5-2, 38 KOs), looked him in the eyes and told him so during the taping their "Face Off with Max Kellerman" HBO special.

"That hunger that he's looking for, that's no longer there and he can't get it back. It's gone," Bradley said. "It's gone. It is, Manny. It's gone. It's not there anymore. I truly believe that. The killer instinct, that's what I'm saying. He's not the same as far as that."

Pacquiao didn't argue with Bradley on the point. He just said quietly, "I pray for that, another fire."

Bradley, who claimed his world title when he was awarded a hugely controversial split decision against Pacquiao in their first meeting in June 2012, has continued to preach that same opinion about Pacquiao during fight week.