Why, when the Baltimore Orioles are drawing the best crowds in the 25-year history of the franchise and are dazzling fans with pennant-contending performances, are they for sale?

Jerold C. Hoffberger, the Orioles' principal owner, said he won't answer that question, because it's Not anybody's business."

But other sources familiar with the negotiations say members of the several generations of the Hoffberger family, including many by marriage, are adamant that he sell and soon.

Because of the family pressure, the sources told The Washington Post, they believe Hoffberger will depart from his past practice of canceling deals at the last moment and will sell.

And the buyer will be Redskin President Edward Bennett Williams, sources said.

"I don't think Jerry himself has ever wanted to sell, but the family has told him in no uncertain terms that they want to sell," one source said. "I know that because I've been close to it (the situation).

"The family has been getting no return on their investments. There are some aunts and other people who could use some dividends.

"They've always let him call the shots. But now they've made a decision to go ahead and sell and tyey're close to a deal."

Some members of the Hoffberger family are so insistent on a sale that they have refused to sign legal papers pertaining to other family business interests until a sale is agreed upon, another source, a friend of the family, said. The asking price reportedly is $12 million.

"That is absolutely not true, absolutely not true," Hoffberger said yesterday. "What kind of garbage is that? I can't imagine who's saying that kind of garbage. Our family business isn't known around the world. It isn't true."

Hoffberger, as in the past, refused to discuss any aspects of the sale talks or disclose with whom he is negotiating.

Sources said Hoffberger would like to remain active in the club under new ownership, possibly as a minority shareholder.

But the sources said they did not know if Hoffberger would make such an arrangement a contingency of a sale to the prospective buyer with whom he is negotiating.

If Williams is the buyer, there are indication that partners would be involved.

"All I know is that one of them lives in Maryland and they're not Baltimoreans," one source said. Williams lives in Potomac.

Should the parties reach a sales agreement during the season, it is unlikely any sale would be consumated until after the season. The Oriole shareholders and the American League would have to meet to approve the sale and the process could take weeks.

The Hoffberger family's financial involvements have been tightly guarded from the public. It is not common knowledge, for example, precisely who owns how much of the Orioles.,

But, on file with the Securities and Exchange Commission, is a public accounting to the stockholders.

Oriole stockholders have received dividends only five times in the last 15 years, the latest coming in 1972 when shareholders in Baltimore Baseball Club Inc., earned 50 cents a share.

The many members of the Hoffberger family reportedly own 79 percent --with Hoffberger himself accounting for roughly 25 percent -- of the O.W. Fund Inc. The family, however, will not confirm that figure.

According to SEC documents, the O.W. Fund Inc. owns 68 percent of Baltimore Oriales Inc., which in turn owms almost 74 percent of the Baltimore Baseball Club Inc.

"The family simply wants to get out," said another source who, like the others, did not want to be indentified. "The Orioles are doing beautifully, but I think the family is looking ahead a little as to what might happen."

The Oriole record and the fan support makes the club a far more attractive investment than it was in the past and may be in the future, given the uncertainty of free agency and the collective bargaining agreement between the players and owners that expires Dec. 31.

"They (the family) want to make the best of it while they can," a family friend said. CAPTION: Picture, Edward Bennett Williams