John Riggins apparently has become the highest-paid running back in the National Football League, but the reported $825,000 one-year contract he signed today is not a guaranteed deal.

All indications are that as much as $100,000 of the contract is guaranteed, but the rest is not, according to sources.

This seems to represent a change in the Redskins' attitude toward Riggins, who, at 36, is the oldest running back in the league.

His two-year contract for 1983-84, which was worth $1.6 million, was guaranteed.

Of course, if Riggins makes the 45-man roster, which is all but a certainty, he will get the money anyway.

Owner Jack Kent Cooke would not comment on the terms of the contract. Riggins, who arrived at the team's training camp at about 9:30 p.m., said in a Redskins' public relations release: "I'm happy to be back with the Redskins this year. I will, as I always have, do my very best."

Riggins' attorney, Doug Woloshin, also refused to discuss the deal, which was completed when Cooke and Riggins signed the contract early this afternoon at Cooke's Middleburg, Va., estate.

Coach Joe Gibbs, who met with Riggins at the team's Dickinson College training camp Sunday for "a long talk," said he was glad Riggins' 16-day holdout was over.

"I didn't want to start this year off and think, 'What if John had been here?' " Gibbs said. "I'm happy all the outside interruptions are over and we can start with things (on the field) that are really important."

Gibbs praised Riggins for returning after an injury-filled season in which he gained 1,239 yards. He had back and hip problems and twice checked himself into the hospital in 1984.

"I don't think John needs the money," Gibbs said. "John's got tremendous pride. He knows what kind of hard work this is going to be. He knows he's 36 years old, his hips and everything hurt him last year.

"Knowing John, knowing what drives John, I don't think it's the finances. I think it would be him saying, 'I can do this.' We know he's defying the odds, but he defied the odds at 35."

This contract, like Riggins' previous one, is complicated, including annuities and deferred payments.

Riggins apparently made just $100,000 last season, deferring the remaining amount. According to figures from the National Football League Players Association, Riggins' base salary was $695,000 last season, although another source placed Riggins' 1984 salary at $715,000.

Clearly, he received a nice raise to return for his 14th NFL season. Earlier in the negotiations, Riggins apparently asked for a contract worth about $1.5 million. He also rejected the Redskins' first salary offer, but all indications are that he has accepted a similar offer.

Cooke, who said Friday that he expected Riggins to sign today, said he was glad to sign the team's final 1985 holdout.

"I am so enthusiastic about the fact that John is returning to camp," Cooke said by telephone. "The combination of John Riggins, George Rogers, Keith Griffin, et al. Oh boy."

Woloshin said the negotiations ended "with great emotions and a feeling of togetherness.

"It was like two gunslingers putting their guns on the table, testing each other, seeing who would shoot first," Woloshin said. "But it ended in a very positive way."

Riggins had a very good excuse for missing today's practice. After signing the contract, he drove home, packed and began his 2 1/2-hour drive to Dickinson College.

Although reporters and television cameras were expecting him at Biddle Field, the Redskins figured he might be late.

"He's coming in for dinner," Gibbs said. Riggins not only missed the meal, but the subsequent team meeting. He has a press conference scheduled for 11 a.m. Tuesday.

Gibbs declined to give specifics on his Sunday meeting with Riggins, which likely was the final stage in negotiations. Riggins' recent arrest on a drunk-in-public charge probably was one topic.

"There were a lot of things we discussed," Gibbs said. "The talk was between him and me. It was just a personal talk to start the year out. There were a lot of things we discussed.

"I think we're both anxious to start on football."

Starting left guard Russ Grimm watched practice with a baseball cap, taking it easy after suffering a strain and contusion of his left calf. He said he will miss one, perhaps two, more days . . . Wide receiver Calvin Muhammad ran on his own around the Biddle Field track, his dislocated left middle finger bandaged . . .

The Redskins waived four players: running backs Greg Jones and Ron Jackson, tight end David Mills and linebacker Keith Biggers. They placed defensive end Willie Roseborough on injured reserve; he had had knee surgery last month . . . The Redskins signed tight end David Hersey, a two-year veteran of the Los Angeles Express of the U.S. Football League who played at the University of Arizona . . . The team's roster stands at 91 players. The first mandatory cutdown date is Aug. 20, when the roster must have no more than 60 players.