The Manny Pacquiao who unanimously decisioned Brandon Rios in November won't beat the Timothy Bradley who defeated Juan Manuel Marquez in October, according to Larry Merchant.

"You can't say enough about Manny and where he was when he first came to America, and how he evolved as a boxer-puncher," Merchant told RingTV.com. "In that fight, against Rios, he fought just as a boxer. But he's not going to be able to beat Bradley just as a boxer. You can never dismiss a fighter of Manny's proven qualities.

"It's not like the man has had one bad round in 10 years or one bad 10 seconds," Merchant continued. "So you don't just dismiss him because he showed that he's still eager to do it in his last fight. The quesion is whether he can make as big a change in doing that as he would have to to beat Bradley. The question for Manny is whether he will have the ability and the fire to force a fight, and to return a little bit to his previous incarnations.

"But Tim Bradley is a younger guy and he still thinks that he's got stuff to prove, and that's what makes Bradley who he is," said Merchant. "Bradley wins every place that he goes. If there is any resistance, he wears you out. He's a damn good figher."

In his last two fights, the 30-year-old Bradley (31-0, 12 KOs) took considerable punishment but outpointed Ruslan Provodnikov via close unanimous decision last March before defeating Marquez.

Pacquiao (54-5-2, 38 knockouts), who turned 35 in December, rebounded from the split-decision loss to Bradley in June 2012 and a knockout loss to Marquez in December 2012 by easily outpointing Rios.

Bradley and Pacquiao will meet again on April 12 at the MGM Grand in Las Vegas, the site of their previous meeting.

"Against Marquez, Bradley showed that he's recovered from the Provodnikov fight, and he showed that he still was a hard guy to beat, and that he could still box against the best," said Merchant of Bradley, who reportedly fractured his left foot and sprained his right foot in the first Pacquiao bout.  "I think that if Bradley goes out with that attitude against Manny, then it makes Manny have to make the fight, and that will make it a helluva fight. In the first fight with Manny, he came out trying to show that he could fight with Manny, but then, after three or four rounds, he started to box him and he did better. I think that it's pretty clear that Bradley is going to try to come out and fight Manny the way that he fought Marquez, and that's to out-box the boxer."

"If Bradley does that, then that's going to put the burden on Manny, who is the older fighter. At the very least, Manny Pacquiao has got to make it a helluva fight. I think that it's a tossup fight. … Most people see this as a tossup. If Manny is favored, it would be primarily because of his fans backing him. It wouldn't surprise me at all if he lost in this fight. Pacquiao certainly can't fight Tim Bradley the way that he fought in his last fight against Brandon Rios. I don't know that he can fight Bradley when Bradley is fighting the way that he fought against Marquez. What I saw in the Rios fight from Manny is that you saw that he still wants to fight, and that he's in shape. He showed that he had another re-invention of himself and that's as a pure boxer for that opponent."

Pacquiao has promised to bring back his "killer instinct" for his return bout with Bradley, who questioned Pacquiao's resolve against Rios.

"Manny didn't look the same against Rios. He didn't have his usual killer instinct," said Bradley. "That's the first thing I noticed. I don't think he has the hunger anymore and it's never coming back. He no longer has his killer instinct."

Pacquiao picked up on that notion, saying that his passion has returned. 

"What Bradley has been saying to me is that the killer instinct and the aggressiveness is not [there] anymore, and that I don't have that anymore. So that's what I'm trying to prove this fight on April 12. I think that he's right. Maybe I'm just too kind and too nice to my opponents sometimes in the ring," said Pacquiao, during an earlier interview.

"Yes, I'm just too kind and too nice to my opponents sometimes in the ring, and that's why you can not see the aggressiveness and the killer instinct. But this time around, I have to get it back and show that I still have that aggressiveness and that killer instinct. … To all the people who love boxing, don't miss this fight. It's going to be more action in the ring and you're going to see, in both of us, a young Manny Pacquiao and a young Tim Bradley in the ring."