Former Navy running back Napoleon McCallum has signed with the Los Angeles Raiders and is expected to play in the NFL team's first preseason game next month, but he won't join the team full time until his five-year military commitment is over, the Raiders said yesterday.

Raiders officials and Darryl Dennis, McCallum's Washington-based agent, refused comment on terms of the agreement, signed within the last two weeks. But an informed source said McCallum's contract "ranked as one of the top offers this year," adding it was "equivalent" to that of first-round draft choices.

What with his service obligation, McCallum, holder of 26 Naval Academy rushing and receiving records, was not selected until the fourth round of the NFL draft.

The Daily Breeze newspaper in Torrance, Calif., reported that McCallum received $100,000 immediately, part of a $700,000 bonus he will get when his mandatory tour of duty ends.

McCallum, now an ensign working in the Navy's Los Angeles recruiting office, will use a 30-day leave to attend the first four weeks of the Raiders' training camp in Oxnard, Calif., according to Dennis.

He is expected at camp Wednesday with the other rookies and most likely will play in the Raiders' first preseason game at San Francisco Aug. 10, said Ron Wolf, Raiders director of personnel operations.

His leave will be over before the next preseason game, and he is not expected to have any more time off until next year. The Navy allows 30 days leave a year, said Kendell Pease of the Navy's public information office in Washington.

"We signed him for any eventuality whenever he becomes available to play," said Raiders owner Al Davis. "We signed him now because we wanted him to come to camp. He is a first-round quality player. There's no question this guy's a great player, and we're willing to wait for him."

McCallum could not be reached for comment.

Under NFL rules, an unsigned player may not participate in training camp. If the Raiders had not signed McCallum before next year's draft, they would have lost his rights.

As far as the Navy is concerned, McCallum is free to do virtually as he pleases during leave and may keep any extra compensation.

"I'm not going to break down what he can and cannot do, but he is allowed to go to the Raiders' summer camp," Pease said. "You can work other jobs in the Navy. I could teach school if I wanted to. It can't be a conflict of interest or a perceived conflict of interest, but he certainly is allowed to work."

But he cannot do endorsements or commercials, Pease said.

"After all, he's in the Navy."

McCallum is expected to be assigned to a duty station in Long Beach, Calif., once his leave is over.

On June 28, he married Karen Shelton, of the Los Angeles area, at the Academy chapel in Annapolis.

McCallum, who set the NCAA record for all-purpose yards with 7,172, rushed for 1,327 yards last season and scored 15 touchdowns. In an unprecedented move, the Naval Academy granted him an extra year of eligibility after he broke his leg early in the 1984 season.

McCallum's professional situation is not unique. The Dallas Cowboys drafted Navy quarterback Roger Staubach and waited out his military obligation in the 1960s.

More recently, the Atlanta Falcons signed Navy running back Eddie Meyers and the New York Giants, wide receiver Phil McConkey, who since has left the Navy. CAPTION: Picture, Napolean McCallum is said to have received $100,000 of a $700,000 bonus.