Ralph Sampson, Virginia's 7-foot-4 all-America center, is leaning heavily toward remaining in school for his fourth and final year of college basketball and not turning professional until his class graduates, in 1983.

Sampson, college basketball's player of the year the past two seasons, has until midnight Saturday to notify the National Basketball Association if he wishes to forgo his final year of college basketball and be eligible for the NBA's June draft.

Terry Cummings of De Paul, Dominique Wilkins of Georgia, Quintin Dailey of San Francisco and LaSalle Thompson of Texas already have declared availability for the draft. North Carolina's James Worthy and Ohio State's Clark Kellogg, like Sampson, have held off their decisions.

Sampson said after the season he probably would not announce his decision until Friday or Saturday. He has been unavailable for comment this week. But several sources close to Sampson told The Washington Post this week that he will almost certainly stay for his senior year.

In the three years Sampson has been at Virginia, the Cavaliers, under Coach Terry Holland, have won 83 of 101 games. Virginia was 30-4 last season, losing in the Mideast Region semifinals to the University of Alabama-Birmingham, after being ranked No. 1 by both wire service polls much of the year. Sampson has averaged 16.1 points a game and 11 rebounds for his three years.

If Sampson decided at the last moment to leave Virginia, he would be drafted by either Los Angeles or San Diego (to be decided by a coin flip at a later date), and probably would earn as much as $1.5 million in his rookie season.

But Sampson, who reportedly has an insurance policy in case of injury, also is considering these other factors:

Should he stay, Virginia likely will again be one of the best college basketball teams in the nation.

The professional money still will be there, even next year. Barring serious injury, or unless Georgetown's Patrick Ewing decides to leave after his sophomore year, Sampson will be the first player drafted in 1983.

Sampson enjoys college life in Charlottesville and the prospect of living in one of the prestigious rooms on "the Lawn" next year. "Only 54 students are selected to live on 'the Lawn' (the area fronting the famed Thomas Jefferson Rotunda) because of the hours of contribution they have made to the university," one source said. "It's the most prestigious honor that can be bestowed on a student while he is still at the school. It has a lot of meaning to Ralph."

Sampson is intent on getting his degree from Virginia. He is a speech communications major, a good student, and currently on schedule to graduate next May.

The people of Charlottesville remain apprehensive, waiting for Sampson's decision, which should come Friday.

Sampson was wooed by Boston Celtic General Manager Red Auerbach after his freshman year, courted by Detroit and Dallas after his sophomore year, and could call his own salary from either the Lakers or Clippers this year. It appears the answer to the NBA this year will remain the same as previous years: no, until June of 1983.

"The prevailing feeling here is that Ralph is gonna stay in school, live on 'the Lawn' and have a great senior year," said Bobby Mincer, an influential Virginia basketball booster who is close to the program. "I suppose life would go on if he leaves. It would be earth-shattering, though."