Professional basketball works from the inside out. A strong center, even when not scoring large amounts, forces the opposition to concentrate on that possibility, which in turn gives his teammates freedom in which to work.

This role is clearly illustrated in absentia by Jeff Ruland, as the Washington Bullets struggle offensively without their injured center.

When he went down with a fractured and severely sprained right ankle on Dec. 11 in the final seconds of a victory over the Detroit Pistons, Ruland definitely was an inside threat, averaging 21 points per game and shooting 58 percent from the field. He also was averaging nearly six assists per game.

He was activated by the Bullets last week and has had his cast removed. Now Ruland is working out lightly with the team and shooting some, although he is not expected to play for another 10 days or so.

Even Ruland's team-leading 4.5 turnovers a game is an indication of how much he handled the basketball and of how much the offense revolved around him. Now, what had been a precise, patterned attack has often been reduced to one-on-one play, a quick way to get nowhere fast in the NBA.

"That's what I miss the most about him, the way we execute with him in the game," said guard Jeff Malone. "Things are just different. The picks get set deeper on the floor so you're that much closer to the basket when you shoot."

That the Bullets have stayed in the vicinity of .500 in Ruland's absence is impressive, but it is little consolation for the fact that before Ruland was hurt, the team had won four of five games.

"It's not much fun watching them struggle and not being able to help, yes, you could say that," said Ruland. The tone of his voice was whimsical, a touch sarcastic.

It is a tone used often by Ruland, particularly in times of trouble. Perhaps a touch of levity to mask the hurt he feels, a sensitivity that he is reluctant to announce out loud.

Ruland, as team captain, obviously is respected and well liked by his teammates. He's very much in the center of things and yet, at the same time, he is not one of them. In an era when many athletes are as concerned with the stock market as the win-loss standings, Jeff Ruland is a throwback: he just wants to win.

"That's what I like the most about him," said Bullets Coach Gene Shue. "He's just so damn competitive. There aren't a lot of guys in the league like that; a lot don't care. He does, and every night you know that you're going to get everything he has."

Ruland acknowledges the difference but is at a loss to explain it. "I don't know, maybe they just have other priorities," he said. "I just like to win. Even if I'm playing backgammon at home with my wife I'm trying to kill her."

Ruland's main priority at present is to get back into the lineup and back to full strength. One day after the knee-length cast on his ankle was removed, he was lifting weights.

When he returns, Ruland may find himself en route to becoming the answer to a trivia question of sorts: Who is the only man in the NBA to earn the comeback player of the year award twice in the same season? The success that the 27-year-old center enjoyed earlier in the season and hopes to enjoy after he rejoins the team is coming after his return from a debilitating injury last year.

It was a little more than a year ago, on Jan. 14, 1985, that Ruland hurt his right shoulder in a game against the Cleveland Cavaliers. He would miss all but one of the remaining regular-season games. With Ruland out again with a debilitating injury, the question arises: Has the Bullets' big man gone brittle?

"It was as much pain as I've ever felt in my life," Ruland said of his most recent problem. "I almost passed out trying to walk over to the bench to sit down. It happened again going to the locker room, trying to get into the van and in the hospital, too."

The idea of a 6-foot-10, 270-pound man nearly passing out four times seems stunning, but no more so than the idea that Ruland would be struck down for prolonged periods in consecutive years. Besides his scoring, rebounding and passing, the most impressive statistic regarding Ruland is his durability. At the time of his injury, he was averaging 40 minutes of playing time per game this season, about par for the course for his five-year career.

Given the incessant pounding and contact that accompanies his style of play, though, it was perhaps inevitable something would give.

"I was fortunate enough to play without injury until last season, but it was something that was bound to happen," Ruland said. "I'm not worried about it (being a permanent problem). I still love what I do.

"I mean, look at those people who are out on the Beltway every day fighting traffic in, working nine to five, then getting stuck and fighting traffic out. I could be sitting there with them."

Somehow, that scenario isn't too hard to envision, given Ruland's workmanlike approach to basketball. Even with his return, the Bullets may be hard pressed to come anywhere near those championship rings of which the center so often speaks. It's not that he wants the extra money or even the sensation of having champagne poured atop his head before a television camera; it's that he views it as a measuring stick.

"Whatever it was that I did for a living, I'd want to do the best possible job that I could," Ruland said. "In the NBA, that means winning a championship."

Milwaukee Bucks Coach Don Nelson doesn't think that's too far-fetched.

"If he's back when they say he'll be back, then the Bullets will have enough time to put it back together," Nelson said of Ruland. "If that happens they'll be a very nice team going into the playoffs." McMillen's Foot Put in Cast

Washington Bullets forward Tom McMillen had his right foot placed in a cast yesterday after team physician Stephen Haas diagnosed the injury as a ruptured tendon, according to a Bullets spokesman.

McMillen will be reexamined in 10 days. He was injured with about six minutes left in the fourth quarter of Sunday's game against the Chicago Bulls, which the Bullets won, 112-98.