Just before 4 a.m. Sunday, a reign of terror broke out at the Cross Keys Inn. A man began telephoning members of the Boston Red Sox in the middle of the night and yelling in their ears.

The culprit was Red Sox Manager John McNamara, one of the most tight-lipped men in baseball. What had driven good ol' Johnny Mac out of his right mind?

"We got Tom Seaver!"

Those were McNamara's words to one Red Sox coach after another.

Diagnosis: insanely happy.

Not everyone was delighted, of course. When Don Baylor, judge of the Red Sox kangaroo court, got word that Steve Lyons was dealt for Seaver, he was furious. Lyons, the Red Sox' top space cadet, specialized in all the mental gaffes for which Baylor levies $5 fines.

"Trading Lyons took away our major source of income," said Baylor, who is saving the money to throw a team pennant party. "If Seaver's not here by the first pitch today, he's fined. I don't care if he's got to fly all night to get here. I've got to make up the deficit somehow. President Reagan has his problems; I got mine."

It's hard to find a Red Sox problem. Unless you count McNamara's bloodshot eyes. By evening, after his club had swept a three-game series from Baltimore and pushed its division lead to eight games, he looked as if he could barely stand. "I slept an hour," he fibbed.

Who needs sleep? The Red Sox are running on high-octane joy. Remember 1918? Seems like yesterday, doesn't it?

For any follower of the Red Sox who is younger than President Reagan, this could be the only season of a lifetime when a World Series flag flies above Fenway Park.

No, it's not too early for fantasy. In the last two weeks, the Red Sox have just about won the AL East pennant. Of course, they may yet find a way to unwin the cursed thing. T w0105 -0/86-BOSWEL 1stadd w0105 06-30oe Sambitoect capsule comment: "We get Seaver. The team motto: Grind everybody ts go for 20.' "

But couldn't going to the whip so early tire out a pitching staff?

"If we're 14 games ahead in August," said Baylor, "tch."

He probably won't be Ed Romero badger umpire Nick Bremigan after Romero was picked off first base by Orioles' Mike Boddicker. (WP)