PITTSFIELD — A collector intent on acquiring Berkshire Museum works could be waiting in the wings, an attorney said, ready to leap.

When an injunction barring sales of museum pieces expires in less than two weeks, the institution could work with Sotheby's to put the most prized works in new hands, even as litigation continues.

"If there is no restraint on the sale, then there is no restraint on the sale," said Nicholas M. O'Donnell, a partner with the Boston firm Sullivan & Worcester LLP. He represents three Lenox residents opposed to the museum's plan to raise money for operations by selling 40 artworks.

O'Donnell said that when an injunction expires Jan. 29, nothing prevents the museum and Sotheby's from proceeding to a swift private sale for at least some of the works, provided that buyers can be found.

Those buyers would have to be willing to pay sums close to what the works were expected to bring at auction. Two paintings by Norman Rockwell led the list for a planned Nov. 13 auction that was canceled after a first injunction was granted. Bid estimates hit a high of $40 million for those two pieces alone.

"They're not going to turn down a sale," O'Donnell said Wednesday.

"That's what they do — and do very well," he said of the auction house.

Though the museum's consignment contract with Sotheby's states that 40 works will be sold at auction, the two parties could renegotiate that agreement.

Darrell Rocha, a spokesman for Sotheby's, could not be reached for comment on the possibility of a private sale.

Several high-profile collectors are known to pursue Rockwell works. They include filmmakers Steven Spielberg and George Lucas and Alice Walton, creator of the Crystal Bridges Museum of American Art in Bentonville, Ark.

On its website, Sotheby's explains how clients can obtain its help selling works privately.

"Sotheby's offers private sales in all the categories in which we also conduct auctions," the site says. "When you consign a work to Sotheby's for private sale, we will present you with an agreement outlining our exclusive right to offer the work for a specified period of time. Sotheby's will then begin to discreetly offer your property to individual potential purchasers, one at a time, while keeping you informed of our progress."

The minimum value for a work consigned for private sale is $100,000, the company says.

Brief filed

O'Donnell cites the possibility of a sale at any time after an injunction is lifted, in a brief filed Tuesday with the Massachusetts Appeals Court. He is asking for a permanent ban on sales, pending a full trial on the legal merits.

O'Donnell's filing is his effort to get his clients back in action, after Berkshire Superior Court Judge John A. Agostini ruled Nov. 7 that they lacked legal standing to challenge the museum's plan.

The museum seeks to close a recurring deficit and to pursue a new direction through the sale of artworks. Without taking dramatic action, trustee have said, the museum risks closing in eight years.

O'Donnell's appellate brief argues that Agostini erred on the issue of legal standing for his clients, James and Kristin Hatt and Elizabeth Weinberg.

His brief claims that museum trustees violated their own collections policy when they entered into a contract with Sotheby's in June to sell the works. That policy was changed July 11, a month after the deal was inked.

"It's our argument that when the contract with Sotheby's was signed, that contract violated the collections management policy in place," he said.

During a Nov. 1 hearing in his courtroom, Agostini sharply challenged the notion that museum members hold grounds to second-guess decisions made by trustees. O'Donnell argues in his brief that Agostini's ruling was based on incomplete information.

"They have a right to good governance," he said Wednesday of his clients. "And that's what we think has failed."

O'Donnell asks the Appeals Court to send his civil action back for trial in the venue where it was filed, the Business Litigation Section of Suffolk Superior Court.

The case was combined with another lawsuit and heard instead in Agostini's court. O'Donnell said he believes the Suffolk court is a better venue because it handles specialized business issues that he believes apply in how the museum's bylaws are interpreted.

Larry Parnass can be reached at lparnass@berkshireeagle.com, at @larryparnass on Twitter and 413-496-6214.