Seldom does a baseball team face a personnel decision as difficult, and as worrisome, as the managerial choice the Baltimore Orioles say they'll probably make in the next couple of days.

How do you find one man to replace Earl Weaver?

You don't.

That's why the Orioles desperately want to replace him with three men.

It's an open secret that, with a press conference tentatively set Friday, the Orioles have narrowed their search to Joe Altobelli, Ray Miller and Cal Ripken Sr. What isn't so commonly perceived is that the Orioles' fondest wish is to have all three. It's a solution that seems so solid to the Orioles that they can actually visualize themselves improving in their first post-Weaver year.

Taken as a triumvirate, sharing in decision making, these three might give the Orioles most of Weaver's strengths and fewer of his weaknesses. But this could be thrown out of whack if, as the team fears, Miller is hired away by Oakland.

If things work out as the Orioles would like, Altobelli, 50, would be manager. He's the front-running candidate at this 11th hour, with Miller the only realistic dark horse. Altobelli, with his half-cop, half-priest manner, would provide dignity, experience, an occasionally explosive temper and an ability to discipline players.

It doesn't hurt that Altobelli managed nine of the present Orioles when they were in Triple-A, or that he has a National League manager of the year (1978) plaque to his credit. If Altobelli is hired, no one in the organization will be insulted; after all, he was next on the ladder to succeed Weaver as far back as 1975.

In short, Altobelli would be tough, emotional and respected, as Weaver was. If Altobelli lacks Weaver's showmanship and spark, he might also lack his knack for irritating players and enraging umpires.

Inevitably, Altobelli also will not have Weaver's aura of creativity and preternatural "baseball judgment." Altobelli, with his 225-239 record managing the Giants, won't get the benefit of the doubt that players extended to Weaver.

In almost every area, Pitching Coach Miller is the foil and complement to Altobelli.

Miller's bright, experimental, funny, slow to anger, close to players, a teacher. At 37, he's so confident in his judgments that, for much of 1981, he played devil's advocate with Weaver, bluntly but loyally disputing him.

One reason for the Orioles' 33-11 finish was that Weaver finally, though reluctantly, came to agree with a half-dozen distasteful notions that Miller had been promoting on behalf of many players.

Platoon Dan Ford, Ken Singleton and Al Bumbry. Use Benny Ayala, Terry Crowley and Jim Dwyer more. Play Gary Roenicke regularly. Stop leaving Jim Palmer in a game when he wants to come out. Stop warming up relievers too many unnecessary times. Use Storm Davis more. Stop giving Cal Ripken Jr. tips.

Perhaps, in part, the Orioles finished strongly because the team finally was being managed in accordance with its internal lobbying. Miller's quiet work as locker room liaison helped turn a potential revolt into a glorious farewell for Weaver.

Altobelli needs this guy. Why? Because he would take over a team with orders not to change it. That's unique, since 99 percent of managers are hired to bring change. Miller, therefore, could be invaluable.

An Orioles clubhouse that lost both Weaver and Miller might find itself in danger of terminal brain drain.

Finally, the stable, workmanlike Ripken is important to the mix because he has been the gruff-but-caring father figure to many Orioles for many years. Ripken has the homey qualities, the warmth, that Weaver believed was incompatible with leadership. Miller may be a sort of older brother, but Ripken is the most affectionately regarded Oriole coach.

Also, Ripken has Weaver's stamp of approval. If Altobelli wants a friend to whom he can whisper, "Ol' Buddy, what would Earl have done here and why?" Ripken's his man. Ripken is the best insurance that The Weaver way will be continued.

As a bonus, both Miller and Ripken are close to Altobelli. Months ago, Miller said, "I hope one of our coaches gets the job. Or Joe, because he's family, too."

Just two weeks ago, all of this seemed part of a cozy scenario. After all, if the Orioles do one thing well, it is evaluate people and anticipate how they'll interact. Perhaps no team makes such consistently sensible decisions on club chemistry.

The Altobelli-Miller-Ripken mix, plus perhaps a new coach or two of Altobelli's choosing, seemed promising. In the short term, Weaver might hardly be missed. Only over a period of years might his gift for retooling a team on the fly be seriously missed.

All that, however, was before Miller became a serious candidate for the A's job; he and Montreal Coach Steve Boros are probably the top two choices.

Why would Miller leave the Orioles after they've been so good to him? Little reasons. Like money.

The Orioles fear that, after they name Altobelli manager, the A's will offer Miller the job managing in California and he'll take it as a consolation prize.

Where will the Orioles' chemistry be then? Will Altobelli look like so wise a choice if one of the legs of the triumvirate takes a walk?

For an economy-class organization that has little margin for error in its major decisions, that prospect is making the Orioles very nervous this week.