The Redskins yesterday signed starting linebacker Rich Milot, one of 16 free agents from their Super Bowl championship team, to a four-year contract worth more than $850,000. Milot's base salary last season was $72,000.

Running back John Riggins, the most valuable player in the Super Bowl and one of the team's remaining 15 free agents, met at least once with owner Jack Kent Cooke yesterday. Cooke declined comment on the meeting; Riggins was unavailable for comment.

Last week, the Michigan Panthers of the new U.S. Football League offered Riggins a three-year contract worth about $2.5 million, according to two sources.

The Redskins have said they plan to sign Riggins, who was the team's highest-paid player at $330,000 last season.

Cooke rarely is involved directly in negotiations. The last player he negotiated with was quarterback Joe Theismann, who last season signed a four-year contract worth approximately $1.4 million.

He also negotiated directly with free agents Renaldo Nehemiah and Bruce Clark, neither of whom signed with the Redskins.

Milot, who started the first game of his rookie season in 1979, also had been offered a significant pay raise to jump to the new league. He said the Philadelphia Stars offered him a contract Tuesday that would have come close to tripling his base salary with the Redskins. At the time, he said he felt he had been poorly paid by the Redskins.

Milot declined to discuss terms of the contract other than its length. "It's a contract for four years that I can be very happy with, that I can play for. It doesn't mean I can live in McLean or anything," said Milot, a Herndon resident.

"The new league was a good alternative," he said. "Four former teammates of mine play with the Stars and there was a good chance I could have played with Philadelphia. It's good for the players in the NFL to have a rival league. I wish the USFL all the success in the world."

Milot's package reportedly was larger than that offered by the Stars and includes base salary, signing and reporting bonuses, incentive clauses and money for which Milot will buy injury insurance. The Redskins apparently retained their policy against guaranteeing contracts.

"It's just an injury guarantee, on or off the field," Milot said. "If I'm not good enough to make the team, they should cut me or get rid of me. But I don't think they should cut me because of my salary, and I don't think they will."

According to Milot's attorney, Richard Bennett, General Manager Bobby Beathard three times had failed to make an offer on the date promised until yesterday. In a meeting described by Bennett as "direct and very frank," it took about 2 1/2 hours to come to terms.

Beathard declined last night to comment on the specifics of the contract, but said Milot was a player of Pro Bowl potential that the Redskins wanted to sign very badly. He said Milot's offer from the USFL Stars gave the player "a little better (bargaining) leverage."

What effect Milot's signing will have on Riggins or the Redskins' other free agents is unclear.

"It's a sign Mr. Cooke wants to keep the team intact," said Bennett, who also represents free agents Neal Olkewicz and Mike Nelms. "It's encouraging for the fans; it's encouraging for the city. But it's difficult to draw any conclusion than they made it clear they wanted to keep Rich Milot. It doesn't mean they'll treat all players equally."

Some feel that Milot's contract is a significant indicator of the competition that seems to be arising between the NFL and the USFL, and the attendant salary changes that could result if it becomes as intense as the competition that led to the NFL-AFL merger in 1967.

According to pro football sources, Milot's $72,000 base salary was just about at the median of $71,500 for the league's 257 linebackers. Only 23 were paid a base salary of $150,000 or more.

Among fourth-year linebackers, the average base salary in 1982 was $78,836 and the highest was $165,000. However, the next-highest salary was significantly lower. Among fifth-year linebackers, the average salary was $93,423 and the highest was $120,000.

Salaries are expected to increase about 30 percent next season as a result of the new collective bargaining agreement that sets minimum pay scales according to experience.

Milot was the first Redskin to start as a rookie since Bill Brundige in 1970. Sometimes out with injuries, he has started all three linebacking positions in the Redskins' 4-3 alignment.