By Mark Lamport-Stokes

LOS ANGELES (Reuters) - Manny Pacquiao will be one month shy of his 38th birthday when he challenges World Boxing Organization welterweight champion Jessie Vargas in November, a mature boxing age that gives his trainer cause for concern.

Though Hall of Fame trainer Freddie Roach is confident that Pacquiao still has "a lot of fight left in him", he has told the Filipino southpaw that the very first time he sees him a step slower in the ring, he will have to retire.

"I do have some concerns over his age. I put all the factors together and so forth and I have a deal with Manny," Roach told Reuters. "I tell him, 'When you start slowing down just one step, I'm going to tell you to retire.'

"We have an agreement that he will retire when I tell him but I haven't seen that step lost yet. In his last fight, he fought a very good fight. We saw a lot of aggressiveness come out of Manny.

"He has the killer instinct coming back and I like that a lot. With his religion, it (the killer instinct) got away from him for a little while but he is very dedicated to his religion also and that makes the training a little more difficult."

Pacquiao, an eight-division world champion, scored a unanimous decision win over American Timothy Bradley in his most recent bout at the MGM Grand in Las Vegas in April.

That was his first fight in nearly a year after his loss to undefeated American Floyd Mayweather in a heavily hyped welterweight showdown, and it improved his career record to (58-6-2).


Though Pacquiao announced his retirement from the ring after beating Bradley and was then elected to the Philippines' senate in May, Roach never doubted that the Filipino would make a boxing comeback.

"He still knows what he does best, and that's boxing so him making a comeback this quickly wasn't a big surprise to me," said the bespectacled Roach. "I know he still loves boxing, he still has a lot of fight left him."

Asked if Pacquiao would be making a one-and-done comeback, Roach replied: "No. he will definitely fight a few more times after November 5.

"We would like to get a Mayweather re-match done before we are done. Manny thought we won that (first) fight but I didn't."

In what was billed the "Fight of the Century" in May last year, Pacquiao lost on a unanimous decision to Mayweather Jr but said later he had been hampered by an injury to his right shoulder that he suffered during a pre-bout sparring session.

"The thing is, if Manny didn't hurt himself in the fourth round against Mayweather, I think it would have been a big difference," said Roach, who has been voted trainer of the year by the Boxing Writers Association of America on seven occasions.

"We would love to get Mayweather back in the ring (out of retirement) and if Mayweather doesn't come, there is this young kid, Terence Crawford.

"He's a good fighter and he might be the next Mayweather," Roach said of Crawford, 28, who is the WBO and WBC light welterweight champion. "He can run like hell. We'll see."

(Editing by Frank Pingue)