For the next week, the Baltimore Orioles will be in one of those periods of crisis in which a baseball team defines itself. Or fails to do so. At this hour, the Joe Altobelli Era is having its first of many tests.

How the new manager and his team endure their first serious slump together, and how soon they regain their equilibrium, will go a distance toward revealing how much the Orioles will miss Earl Weaver over the long haul.

Until a week ago, Altobelli and his chipper Birds were on their post-Weaver honeymoon. Few injuries or harsh words, a cheery 23-13 mark. It proved little.

Winning streaks are interesting, but only slumps are truly fascinating.

When a fine team is caught in a vise between pressure and panic, as the Orioles have been for a week, the sight is riveting.

Watching the proud Orioles lose seven straight games (longest losing streak in the American League this year) by a 51-16 margin, six of them to the Toronto Blue Jays and Minnesota Twins, clubs that finished last in their divisions last season, is genuinely engrossing. Even to the Orioles.

"When you're winning, you tend to overlook your own weaknesses. That's just the way people are," said Altobelli over the telephone yesterday, his 51st birthday. "But when you're losing, a lot of things have a way of being put up front. You see your own team more clearly. This has been educational for me."

A less diplomatic manager might have said:

Dennis (3-8) Martinez had better get going; Eddie Murray, with no homers in 31 games, stop chasing junk; Jim Palmer, stop babying yourself. Sammy Stewart, please throw strikes; Leo Hernandez, go to the opposite field before the count is 0-2; Rich Dauer, Rick Dempsey, Al Bumbry and Ken Singleton, you better start hitting or you might start sitting.

"You don't learn much about yourself when you're winning," said pitching coach Ray Miller yesterday from Kansas City, where the Orioles began a four-game series in the park where, under Weaver, they played their worst. "But you learn a lot about everybody when you start losing.

"There's a lot of pressure right now. In the dugout, when you see all these bizarre things going wrong and everybody seems snakebit, you just want to scream, 'Why me?'

"Everybody talks about 'team character' in sports. These are the times when it gets built . . . The manager and coaches can't panic, or then it gets bad."

Under Weaver, the thing that the Orioles did best was endure. Coping with defeat was Weaver's specialty. Some veteran players don't need to have their hands held. For instance, John Lowenstein, asked this week why he was zero for 24, pointed at the field and said, "Abner (Doubleday) put too many people out there with gloves."

Some Orioles, however, needed the unpredictable Weaver touch.

Whether he was philosophizing for the team's consumption in the press, hollering in the players' faces in the dugout, joking with them an hour later on the bus or throwing a tantrum at an umpire, Weaver had a knack for the galvanizing psychological trick. Now, the Orioles face their first nose dive without him.

True, the Orioles have a 23-20 record, two games ahead of 1982. And the teams they'll have to beat, Milwaukee (21-18) and New York (20-21), are suffering just as much. "When you lose six straight but only lose a couple of games in the standings, that's not something of disastrous proportions," said Altobelli.

However, look what's stacked against them. First, they play seven straight games on AstroTurf in K.C. and Minnesota, two parks the team dislikes. Then, 10 days hence, the meat of the schedule arrives: 19 games with the Brewers, Yankees and Red Sox in 24 days in June.

Next, Palmer continues to postpone his return from the disabled list. He's started three games in two months; some teammates are steamed at a $600,000 pitcher who can't or won't pitch with some pain. When Mike Flanagan went down for two months with a knee injury 10 days ago, Singleton said archly, "I doubt if Jimmy'll hurry himself any getting back." Flanagan, perhaps trying to needle Palmer off the disabled list, said, "I've told Jimmy I'll beat him back."

Now, even Miller, usually a defender of Palmer, says, "I'm not smart enough to figure Palmer out. I'm not even going to think about him until the day he comes up and says, 'I'm ready.' Every time I get him lined up to pitch, another doctor comes up with something new that's wrong . . .

"I look at his page in the record book. A man who's done those things has to be respected and consulted."

"We thought Palmer would start tonight's game," said Altobelli yesterday, "but that's not to be. He'll join the team in Minnesota and we'll see how it stands then . . . It gets frustrating, because he's sorely needed at the moment."

The sudden losing streak, materializing from thin air, then settling around the throat, is the terror of every contender. Ask the Atlanta Braves, who lost 19 of 21 games in three weeks of paralysis in 1982.

"It never hurts a person to eat a little humble pie," said Altobelli.

A little, yes. But the trouble with humble pie is that, once you've had a slice, sometimes you eat the whole thing.