Usually, when a team fires its manager as a scapegoat, the club's management at least pretends that sensible and urgent baseball considerations were preeminent in their thinking. The Boston Red Sox, however, had the decency today to admit that they fired Don Zimmer this morning for all the wrong reasons.

General Manager Haywood Sullivan, who said he did not finally decide to terminate Zimmer's services until 11 a.m. this morning and has not yet decided on a new full-time skipper, cited "economics, fan reaction, public relations and on-the-field thinking" as reasons for canning the Bosox manager of the past 4 1/2 years. In other words (in order), Zimmer was fired because Red Sox attendance is down almost a half-million the fans are booing and a change of managers might be a good image-polishing move to con the fans into being enthusiatic boosters again.

That final Zimmer dificiency -- "on-the-field thinking" -- is presumably a reference to the general impression hereabouts that Zimmer doesn't know whether his floundering pitchers are rare, medium or well-done.

In typical fashion, Zimmer, a 32-season baseball man, showed up for his own press conference-funeral, sitting shoulder to shoulder with Sullivan, the friend who had to fire him. "I've never had a job where I didn't have a baseball uniform on," Zimmer said, "and I'm not going to change that yet. I'll be in another uniform -- on the field, probably as a third base coach -- next season." Thus did Zimmer refuse the Sox offer of a front-office job.

Ironically, Zimmer's many critics in Boston were much more vociferous after the '78 and '79 seasons. This year, he has generally gotten good reviews for bringing a much-injured and often dispirited Boston team home safely above .500.

Right until the last minute, I never thought they would fire such a solid baseball man," said Coach Johnny Pesky, who will be the titular interim manager until Sullivan makes a decision"by World Series time."

Zim runs a game properly uses his men well," said Pesky. "And he handled the media well, which is important here and in Philadelphia, where the whole town is rabid about baseball and second-guesses everything.

Among the prominent names in the early line speculations on the sixth Boston manager since '65 are Milwaukee Coach Frank Howard, Boston minor league Coach Joe Morgan and Baltimore Coach Frank Robinson.

"if management asked me what kind of manager we need next time," said Boston shortstop Rick Burleson, "I'd tell them to get a man just like the one they fired.

"In my book, Zimmer was excellent in the way he treated people and ran a game," added Burleson. "The only complaints you might find would come from the pitching staff."