The sale of the Baltimore Orioles to former Secretary of the Treasury William Simon is imminent, barring a last-minute change of mind by club owner Jerold C. Hoffberger, an informed source has told The Washington Post.

Agreement on a price of $12 million has already been reached and final conditions are "in the hands of the lawyers," it was reported. Both Hoffberger and Simon have admitted often that they have been negotiating for several weeks.

The admonition against a late-moment change of heart by the Orioles' owner is related to his pullouts in the past when, with the club seemingly on the verge of being sold, Hoffberger ended negotiations.

In recent weeks, Hoffberger has been more positive than ever in sounding his desire ot unload the team that he and his family have controlled since 1965. "I'm tired of hearing of myresponsibilities (to Baltimore)," he told the Baltimore Evening Sun Monday. "I've busted my... for 20 years with this club and I'm fed up."

It is also known that Hoffberger has been under pressure from other stockholders in his family to sell the Orioles, who have not been a good investment.

The tilt toward selling the team to Simon has been emphasized with the failure of a B altimore civic group to show money strength to Hoffberger in its bid for the team. "As usual, these civic people are long on talk and short on cash in these takeover attempts," The Post was told.

Simon, who was unavailable for comment yesterday, is represented in comment yesterday, is represented in the dealings by Washington attorney Robert A. Schulman, who has been involved in National Football League legal affairs and is known for having other important clients. When Simon was asked several days ago about prospective partners, he said:

"I would welcome partners but I can handle it alone if necessary."

Simon has avoided the questions of newsmen since starting his dealings with Hoffberger. As for a plan to play a certain number of games in Washington if he did purchase the team, Simon has said only, "That could be a possibility."

Others pointed out, however, that Simon is Washington-oriented from his term as Treasury secretary in the Ford administration and is comfortable on the national scene. "Visualize the opening day of the baseball season," said one source. "Would Bill Simon, as a club owner, rather be shaking hands with the mayor of Baltimore or the presdient of the United States?"

Hoffberger's intention to sell the team has been reinforced by the Orioles' lack of support from the same Baltimore fans who are now urging him to stay in business. "The same guys who won't buy tickets are now asking why I don't keep the club here," he is quoted as saying.

An attempt by some citizens to float a city bond issue to help buy the Orioles and keep them in Baltimore has proved illusory, encountering an official American League frown against such financing.

Another source has reported that "Hoffberger is leaving for israel next week and something definite should be done before he leaves."