Campbell, who has worked with Torres before, believes he can get Torres back to his best pace.
He told the Telegraph: "It's something that is best done in pre-season but I think Fernando just needs two weeks when he hasn't got to worry about playing on the Saturday and just put in a nice two-week training programme that I think would definitely bring the majority of his speed back.
"I'm sure I could fix him. It doesn't have to be a lengthy process because these guys are already extremely fit. That's the great thing about working with footballers and rugby players. You're not having to worry about the base fitness so you just go in and teach the raw speed.
"In the case of Fernando, I think he would also probably need to do a bit of weightlifting as well as the running and the speed drills to put some power back into his muscles. That's why sprinters lift weights, to gain that explosive speed and power."
Since the pre-season, Campbell has been working with Championship leaders Cardiff City, and in particular with Welsh international striker Craig Bellamy on a programme designed to prevent hamstring problems.
"There was an interesting incident against Manchester City at the weekend when Fernando got the ball and tried to knock it out of his feet and go past Vincent Kompany and James Milner, but they both caught him," added Campbell.
"Kompany we know is very quick but Milner is not exactly lightning by any stretch of the imagination, so that told you all you need to know. A striker without any natural speed wouldn't have knocked the ball out of his legs to chase after. It shows that he is playing as if he still believes he has the speed, but he clearly hasn't."