An administrative law judge at the Department of Labor has ruled that former Washington Redskins offensive lineman Dan Nugent's playing career was shortened by three years by back and knee injuries suffered while playing, and he directed that Nugent be paid $102,548 as compensation for the years lost.

The judge, John C. Holmes, also held that under the workmen's compensation laws the Redskins are liable for all future medical expenses for treatment of Nugent's back, from which a herniated disk was removed during surgery in the fall of 1979. Holmes ruled that Nugent's back is 3 percent permanently disabled, and awarded him $1,100 a year compensation for the rest of his life.

Richard Berthelsen, counsel for the National Football League Players Association, said that in recent years an increasing number of former players have sought redress under the workmen's compensation laws.

Gerald Herz, Nugent's lawyer, said that should Nugent's back injury worsen as he gets older, he has the right to seek additional compensation.

Nugent, a third-round selection drafted out of Auburn by the Los Angeles Rams, was acquired by the Redskins after training camp ended in 1976. He did not become a starter until 1978, then started all 16 games that season as an offensive guard. But he injured his knee that season and, in January 1979, injured his lower back while working out with weights trying to rehabilitate his knee.

In training camp that summer he reinjured his back hitting a blocking dummy. The herniated disk was removed that September and Nugent sat out the season on injured reserve.

Against his doctor's advice, Nugent returned for the 1980 season, saw only limited action and was cut before the 1981 season. In testimony before Holmes, Redskins General Manager Bobby Beathard said Nugent was cut because he did not play well enough and that his injury had no part in the decision to release him.

But Jack Pardee, former coach of the Redskins, said the injury slowed Nugent and made him unable to block low. Holmes decided Nugent's "career ended before it should have because of his back injury."

By 1981, Holmes said, "the team was well aware of the risks involved in Mr. Nugent's continued employment as a professional football player . . . being cleared for play in 1981 by the team physician, in the harsh and violent world of football, means little more than that he was not entirely crippled."

A 1981 Redskins' report, Holmes said, indicated Nugent had become "little more than trade bait with little or no chance to make the team."

The money awarded Nugent, Holmes said, was based on the difference between what he would have made had he continued playing with the Redskins another three seasons and his expected $37,000-a-year earnings as an accounts executive at WMAL radio. The station said yesterday that Nugent had quit his job at WMAL and was en route to Florida.

Lon Babby, the lawyer who represented the Redskins in the case, declined comment other than to say he did not think the team would appeal.