The Orioles continued their worst April since 1955 with a 9-6 loss to the Oakland A's tonight. When the game was over, there was a smattering of boos from the sparse crowd of 10,990 at Memorial Stadium, and from the Orioles' locker room came dead silence.

The unprecedented postgame silence lasted 45 minutes as Manager Earl Weaver met behind closed doors with all nine of his pitchers and Ray Miller, the pitching coach. When the meeting ended, still no one wanted to talk.

"I stand mute before my accusers," said Scott McGregor. "That's the last thing I'm going to say."

Reliever Ross Grimsley tread carefully in the mire of the Orioles' gloom, saying only that Weaver told his pitchers, once the bane of all the American League hitters, "to get the ball over the plate. Everybody's been pitching defensively. You don't want to give them too much to hit, but you have to get the ball over the strike zone."

Indeed, Oriole pitchers walked seven A's tonight and five of them scored. The Orioles outhit Oakland, 14-8, but stranded 11 base runners in losing their 12th game of 17 played in this young season.

Said Weaver, after declining any other comment in his smoke-filled office, "The game tonight was marred with bases on balls, and when a game is marred by bases on balls by your good guys, it's not so good."

Added General Manager Hank Peters, "The pitching was brutal. The walks . . . "

Dennis Martinez started for Baltimore, gave up a run on no hits in the first and was knocked out in the second as the A's scored four times on three hits and two more walks.

Grimsley came on to pitch 5 1/3 strong relief innings, giving up only one run on Davey Lopes' third homer of the year. Tippy Martinez replaced Grimsley in the eighth, trailing, 6-3, and the Orioles rallied for three runs in their half of the inning to tie the score.

It looked like a vintage comeback for the Orioles until Martinez yielded a single and a walk to start the ninth and three straight balls to the third batter, Rickey Henderson, who already had walked twice.

Weaver came storming out and called for reliever Don Stanhouse, who delivered just one pitch to Henderson. Ball four. Weaver pulled him and called on the last reliever left, 20-year-old rookie Storm Davis, who had joined the club only Wednesday.

Davis did his level best with the bases loaded and none out in the ninth inning of a tie in the first major league appearance of his life.

But when it was over, after a sacrifice fly, a wild pitch and Tony Armas' excuse-me base hit that glided untouched under the glove of third baseman Cal Ripken Jr., the Orioles trailed by three again.

The A's won two games of this three-game series. Reliever Dave Beard (2-0) got the victory tonight and Tippy Martinez (0-2) took the loss.

Oakland's Dan Meyer, who had four runs batted in, three on a bases-loaded double in the second inning, said of the Orioles' early season woes: "I think it's their pitching more than anything, and (Ken) Singleton's bat. I haven't seen the pitching they had in the past. I used to dread coming here and facing their pitching staff."