Dave Jacobs, who has trained Sugar Ray Leonard since Leonard first put on the glove 10 years ago, said yesterday he is terminating his relationship with the former welterweight champion.

Jacobs said he is leaving Leonard because he disagrees with a decision in the Leonard camp that Leonard's next fight should be a rematch with Roberto Duran, who defeated Leonard for the title June 20 in Montreal.

"My idea is that he should have a tuneup fight before he fights with Roberto again," said Jacobs. "A fight like that takes a toll on a man's body. He needs a tuneup fight to get his timing back."

Jacobs said it was his understanding that discussions were underway for arrangement of a Leonard-Duran rematch. However, Michael Trainer, Leonard's attorney, said final agreement on such a match is "not firm. It is not extremely close."

Appearing at a press conference yesterday to promote the Oct. 2 Muhammad Ali-Larry Holmes heavyweight fight in Las Vegus, Leonard said he wants "to fight Duran as soon as possible."

In Panama City, Carlos Eleta, a handler for Duran, told United Press International that Duran had agreed to fight Leonard at an undetermined site on Nov. 25.

Jacobs quit Leonard once before, in a dispute over money last winter, but he insisted his actions this time were motivated solely by disagreement with the decision to fight Duran next.

"I love Sugar Ray. I've always loved him," said Jacobs."I think he won the fight with Duran, but I don't think it is healthy for him to be fighting Duran again right away."

Trainer said Leonard had met with Jacobs to discuss his opinions. He described the fighter as unhappy over Jacobs' departure.

"We don't go off and do things in a cavalier manner. We're exploring a lot of options," said Trainer. "Angelo (Dundee, another Leonard trainer), Janks and Ray himself, all felt that if another fight with Duran could be made, that would be the logical next step.

"Ray is thought of as a significant fighter. He should be fighting significant fights," said Trainer. "There are few fights in the welterweight division who have not been beaten by leonard or Duran," Trainer said.