A high official in the Massachusetts Democratic Party said last night that Postmaster General Lawrence F. O'Brien probably would not enter the April 30 Masachusetts Primary as a stand-in for President Johnson against Senator Eugene J. McCarthy (D-Minn.).

The official said that O'Brien, who has been widely mentioned as a possible stand-in for Johnson, would be directing the President's national campaign for re-election and couldn't take the time to campaign here in April.

He indicated that the White House had expressed reluctance to have Johnson campaign for himself. "I hope the President will," the official said, "and they still indicate it is a possibility." Senator Edward M. Kennedy '54 (D-Mass.) has said he will not run for the President, and Speaker of the House John W. McCormack has reportedly also been eliminated as possible stand-in.

Meanwhile, John Kenneth Galbraith, Paul M. Warburg Professor of Economics, moved slightly closer yesterday to an endorsement of Senator McCarthy's candidacy. He told Washington newsmen he has "the highest regard" for McCarthy, and he considered the Senator's campaign a "mark of political health."

Galbraith, who is chairman of Americans for Democratic Action, said he had called a meeting of the group's leaders Jan. 1 to consider endorsing the maverick Minnesotan. In a telephone interview last night Galbraith said his statement did not constitute an endorsement, but added that he thought the primary fights would be good for the Democratic Party and good for the country.

"We behave"

At his Washington news conference, Galbraith denied that an endorsement of McCarthy would cause the association of liberal Democrats to break up. "We belong to that wing of the party which knows how to behave itself," he said.

McCarthy's Massachusetts campaign supporters are still having difficulty finding a campaign manager. The group is seeking a member of the Democratic Party in the state who has not been previously associated with peace candidates.

Over 300 Harvard students have signed up to work for the McCarthy campaign, Richard A. Licht '68 said last night. Several students have begun cleaning and painting the Senator's Boston campaign headquarters he added. The office, at 11 South St., is expected to be in operation sometime next week. His supporters have ordered 5000 bumper stickers and 10,000 McCarthy-for-President buttons.