It took John Havelicek most of his 16 seasons in the NBA to develop and refine the swing man's role. In his third pro year, David Thompson already has brought new meaning to the concept.

Havlicek, who in his prime was as gifted and as gutty as any player in the league, still was restricted by average jumping ability and quickness. He overcame many of his deficiencies with some of the purest determination in the pro game has seen.

Thompson has no such limitations. Perhaps no other 6-foot-4 player has ever possessed his dynamic spring. And he has the quickness, moves and shooting eye to confront opponents with a mystifying package of scoring options.

As a result, Thompson is forging new frontiers on the court. He has become more than a swing man who alternates between guard and forward. He now plays an all-purpose position, which is flexible enough to meet whatever demands the Denver Nuggets place on him during a game.

"As our plays are interchangeable as far as positions are concerned," he said. "No matter where I play, a lot of what we do is geared on getting me the ball and letting me go one on one."

Denver allows Thompson the freedom to handle the ball wherever he is most comfortable at the moment. If it's outside, he can pop an 18-footer over a defender. Inside, he flashes a lightning move and then uses his long fingers to roll the ball in from seemingly impossible angles.

He has become what Bullet forward Bob Dandridge calls "one of the hardest people to stop. He's in a perfect situation. He gests the ball a lot, they give him plenty of room to mauever and he has all the ability anyone would want to get free for a score."

Teams constantly are struggling with the dilemma of matching up with him. Do you use a forward and try to handle him with size and strength? Or do you go with a big guard who may have the kind of quickness to stay with him outside?

In effect, Thompson now has turned what once appeared to be a major question makr about his pro career - where would he play - into an asset. By not sticking to any one particular spot, he has made himself into one of the most valuable players in the league.

And, to increase difficulties for opponents, he has emerged as a pressure performer. In close games, the Nuggets wnat him to have the ball and Thompson is more than willing to oblige.

"It has to do with confidence," he said. "You only have two options, to make it or to miss it. I'm a positive thinker and I feel if I take a shot, it will go in. Usually my concentration is greater at those moments because I've been doing it for as long as I've played the game. I know what it takes to do it."

He's proven that consistently since his sophomore year at NOrth Carolina State when he beat Maryland in a classic Super Sunday confrontation at Cole Field House with a skying rebound shot Terrapin fans still can't forget.

The Thomspon magic of those college days has been refined. The tricks are more sophisticated, the sligth-of-hand more calculated, the grand finales even more spectacular. And he believes the best is yet to come.

"I think I'm just getting into this pro game," says the man who is averaging almost 27 points and is shooting 53 percent from the field, "I'm becoming a little more proficient. I can get better because I'm getting more comfortable and more intelligent out there.

"Like with my jumping. I don't jump nearly as much now as I used to in college. I'd go after anything I thought I could block. I tried for the spectacular block. Now I've toned down a little."

This is what a toned-down Thompson has produced this season: four games of at least 40 points, an assist total surpassed by only one teammate and enough dunks to delight even the most casual basketball fan.

He has been voted to the All-Star Team both years in the league, with a record-setting vote total last season. He was selected as a first-team All-League forward last year; the problem now is what position to consider him for in the voting this season.

Thompson is as quiet off the court as he is dazzling on it. His introverted personality is reflected in his aproach to dunking. Although he is capable of spectacular dunks on the level with Julius Erving and Darryl Dawkins, he keeps his repertoire down to the basic two or three needed to handle any defender.

"I'm more concerned with not hurting my hands," he said. "Dunking is easy. Getitng hit by somebody isn't." This is a more mature Thompson talking, someone who has a better grasp of where he is and where he is going.

His coach, Larry Brown, even sees improvement in how Thompson carries himself on the floor. Last year Brown said Thompson "was spectacular but he wasn't great." He felt his star player did all the fancy things expected of him, yet spent much of the schedule "surprised he was able to do it" against the NBA's best players.

Now Thompson is no longer shocked. He is much more comfortable away from the basket than he was last season. And he is much more accustomed to the various ploys defenders have used to try to contain him.

"They try to keep me as far away from the basket as possible," he said. "Inside, they try to get physical. And they try to block the ball on the way up. By now, I think I've seen a little bit of everything.

"But I think I've grown a little more patient in what I do to combat them. I'm handling the ball better and that makes it easier for me to move. I don't force things. If they double-team me when I'm going one-on-one, I look for the open man, things like that."

Teams now are trying different tactics on him. They feel that when he is on defense, he is vulnerable enough to eventually let his mistakes affect his offense. That's particularly true when he is matched up against a guard.

"The word in the league is to run me," he said. "They want to make me work both ends of the court the whole game. And they like to run me through a lot of picks and screens. That way they can bump me around and try to slow me down.

"It works, too, but we have ways of offsetting it, especially if we are picking up full court all the time. Bobby Wilkerson and I will switch assignments and I'll move to a guy who isn't running as much."

What is so amazing about Thompson is that he seems to have been delighting basketball fans for years with his incredible vertical leaps and dunks; yet he is only 23 years old, a mere babe in the NBA Wars.

When Brown says he will be even more devasting in the future, the statement at first seems pure exaggeration. But Thompson's development since his sophomore year at State, when he already was capable of playing in the pros, he been significant enough to assume he can become more polished and more threatening.

Yet, fellow pros like Elvin Hayes wonder how long his knee can withstand the punishment of his skyward thrusts. He already has had one knee operation, prior to State's 1974 NCAA championship season, and he admits some nights he can feel the strain in his legs.

"I know how my knees feel some games and I don't jump as high as he does," said Hayes. "The constant pounding has got to get to them. It got to Dr. J (Julius Erving) and I don't see how he can avoid it."

Those are expensive knees Hayes is talking about. Thompson earns $400,000 a year, one of the highest salaries in a well-paid league, and that total should grow to an even more staggering level when Thompson negotiates a new contract at the end of this season.

But there is nothing he can do about his style of play. It would be like asking a lion not to growl. He says he has learned to cope with the fear of being low-bridged (twice in his career, he has been undercut and has landed on the back of his head) and he tries to keep from becoming entangled in dangerous situations when he leaps.

"I've played for so long that I just don't expect anything to happen to me when I go up," he said. "But I've got to jump. That's me. Without it, well I don't think they'd be paying me what they are."