A baseball team is not an insignia on a cap, nor a mascot in a muppet costume, nor a catchy theme song on the public-address system.

A team is, at its best, a group of men who, over the years, grow to know one another to the bone, know each other to the point where each senses the part that he and all the others play in the functioning of the whole.

Such teams, when they are excellent, are the most compelling subject in the sport. And those teams--real teams--live out a collective destiny. Always.

The Baltimore Orioles are such a group of people who have come to the ripe, full denouement of their communal endeavor. Seven seasons ago, this group of Orioles arrived. By 1977, names such as Flanagan, McGregor, Singleton, Murray, Bumbry, Palmer, Dauer, Dempsey, Martinez and Martinez--yes, that many that long ago--were all nailed above Orioles' lockers. In the years since, they've won more games than any team in baseball. They've been to a World Series and lost in the seventh game. They've won 100 games but lost a pennant race in the final week. They've closed a season with a 33-11 rush and almost completed the greatest final-week comeback in history only to see the flag snatched from them on the final day of the season in their own park.

They have lived a saga together. They'll relive it all their lives.

Unfortunately, baseball teams have a limited life span together. Several Orioles are close to the end of their careers. For these particular O-R-I-O-L-E-S, the time has come to finish their story, or leave the last chapter blank.

Parallels are obvious. The 1976-77 Phillies won 202 games and were nearly great, yet needed a change of managers, from Danny Ozark to Dallas Green, to finish their group project with a world title in 1980. The younger Phillies were better, but the older team won.

The 1977-78 Dodgers, a team together since Albuquerque, lost a pair of World Series, yet came together in 1981 to win a championship. The younger Dodgers were better, but the older Dodgers won it all.

Similarly, the Kansas City Royals of 1976-80 were excellent. But they never won a Series, and now probably never will. Not those particular Royals.

That sense of urgency has hung over the Orioles all season. For them, the change from Earl Weaver to Joe Altobelli seemed a possible solution to their tendency to come up a buck short.

Weaver had given them all he could. Altobelli might provide a different and complementary set of virtues and strengths. They were Weaver's creation, but they needed to play outside his shadow.

That's why the Orioles this season have been the hardest, as well as the most enjoyable team in the AL East to analyze. They have such a rich psychohistory that every shift of fortune, every injury or streak or change of the baseball wind, seems to run through them as though they had one nervous system.

For the last four months, the Orioles have either been the hottest or coldest team in the sport. Baseball may be a game of streaks, but the Orioles are preposterous.

Won-lost statistics aren't usually the life of the party, but the Orioles' record is genuinely unusual. Yet somehow intuitively understandable.

After a 9-8 start this season, the Orioles have gone, in sequence, 14-5, 0-7, 14-4, 5-12, 20-6, 0-7, 7-1. Is this a baseball team or a convention of manic depressives?

Since April 26, Baltimore had had three slumps, in which it's gone 5-26 (.161) and four streaks in which its mark has been 55-16 (.775). Many champions never have one slump in which they play seven games under .500.

In a sense, however, those periods in purgatory are the definition of the Orioles, and their glory. Those slumps show the inherent limits of the club's ability, its vacuum at third base, its dependence on heady platoon players, its doughty determination to win despite a kiddie-corps of starting pitchers such as Storm Davis (10-5), Mike Boddicker (10-6) and Allan Ramirez (4-4).

"This is a remarkable ball club when we win, but it's also a remarkable ball club when we lose," says Manager Altobelli, who has been surprised, almost shocked, by the degree to which the Orioles seem to be self-managed.

"We've had two seven-game losing streaks and we're still 19 games over .500. In those two slumps, I've never seen a club be so under control, and I mean to a man, or darn near to a man. That's as big a compliment as you can pay a team."

At the moment, the Baltimore bullpen denizens have a 1.45 ERA in their last 37 appearances over a four-week period. With Mike Flanagan back and Jim Palmer ready for Sunday, the Orioles look formidable. But no more formidable than they've looked just before losing consciousness in May, in June and in August.

However, no such thought ever infects teams in first place, where even grousing can be delightful. As Rick Dempsey tried to take batting practice today, he growled, "Don't these people have anything better to do than ask for autographs while we're hitting? Don't they know how hard it is to hit .230?"

"What's our magic number?" crowed the infectiously optimistic Rich Dauer. "We're going terrible, but we're still winning. It looks like we've got the best thing in baseball: pitching, defense and timely hitting. All year, we've been awful great or awful bad."

It was on this date that the Orioles began their 33-11 run last season. Then, however, they were 61-57, not 69-50. Despite that apparent advantage, the Orioles remain a somewhat mysterious collection. Today their locker room mood, before and after a victory, was almost sour.

Perhaps it was the presence of both Weaver and Mark Belanger, who were into the Orioles Hall of Fame before the game. Those two ended on awful terms, Belanger blaming the whole 1981 being part of the decision not to re-sign Belanger.

On top of that, the always troublesome Palmer, a love-ore spot in the team group, will return Sunday. Should he lose, or pout, or decide he has a new injury, or do things that infuriate his teammates, could another slump begin?

Even an okay-I'm-here-for-the-glory victorws, since much of the team sees his season as an almost inexcusable sabbatical from competition.

Who knows?oles, who are living out a destiny they only half understand. On the outside, they remain the most confident oe seven-year rookies," continued Dauer. "We're enthusiastic, but we also like pressure . . . We thrive on tough spots because Earl pounded that into us. We made us mentally tough with all his screaming.

"Earl taught us the game," said Dauer, "but Joe lets us play it."