Minnesota Orchestra management has offered what it calls “a further revision to its compromise proposal” in an attempt to settle a contract with locked-out musicians, and its board said Sunday night that it is “awaiting word from the musicians.”

The proposal was offered through former U.S. Senate Majority Leader George Mitchell, who is mediating the long, bitter dispute. No details of the revised offer were released; the process with Mitchell is intended to be confidential.

Sunday was to have been management’s deadline for getting a deal done, to preserve November dates at Carnegie Hall in New York City. Music director Osmo Vänskä had said he would resign if Carnegie Hall canceled those concerts.

However, Vänskä’s only position has been that he needed the orchestra back playing by Sept. 30. Management had made Sept. 15 the deadline in order to ease logistics for getting players back.

The board statement issued Sunday did not mention the deadline, only that “We will share further news as soon as we are able to do so on Monday.”

Meanwhile, musicians played to a crowd estimated well in excess of 4,000, including Vänskä, on ­Sunday at Lake Harriet. In a pre-show news conference, spokesman Blois Olson alluded to some movement over the weekend in the stalemate, which began nearly a year ago.

“It appears the other side has returned to the mediator and is again talking to us through the mediator,” Olson said. “We had conversations with the mediator today, and it appears that new board members have stepped forward, and we are grateful for that.”

He did say that both sides recognize Sept. 30 as a “hard and real deadline.”

Musicians have been locked out since Oct. 1, 2012, after they rejected a contract that would have cut minimum salaries by 32 percent. In July, Mitchell agreed to mediate.

The issue got complicated because musicians said they would not bargain while locked out and management would not lift the lockout. Mitchell proposed a four-month window during which musicians would return to playing. Musicians agreed, but management rejected that idea.

The board then called for two months of negotiations and if no deal were reached, a contract would be implemented that would cut base salaries by 25 percent (down from 32 percent). Musicians rejected that idea.

The board made the new offer in conversations “that have been ongoing this weekend” with Mitchell, it said.

Olson would only say, “There is a long way to go.”

Musicians also announced to the Lake Harriet crowd that if the lockout continues, they will play a series of at least four concerts between now and Christmas. Principal cellist Anthony Ross said the first dates would be Oct. 4-5 at the Ted Mann Concert Hall on the University of Minnesota campus.

Players will perform with pianist Emmanuel Ax, who had been scheduled to play that weekend on the orchestra’s calendar. Ross said Ax agreed to appear “whether we are locked out or not.”

Ross also appealed for funds. He said musicians, who have established a 501 (c) 3 corporation, will match up to $150,000 in donations. Olson said concerts last year made about $40,000 per show.

In addition, local and national benefactors have supported the musicians.

Michelle Price of Plymouth and James Nastoff of Minneapolis, who said they were former series subscribers to the orchestra, rode their bikes to the Lake Harriet concert.

“It’s sad and pathetic that they have to bring in George Mitchell to mediate,” Price said. “It’s gone on too long.”

Nastoff said there are ­certainly two sides to the dispute (“No one is all right or all wrong”), but that he felt the board gave musicians no incentive with its previous proposal to negotiate against a prearranged deal.

“I think there is probably a financial problem,” Nastoff said of the orchestra’s claim that it has a $6 million annual structural deficit. “But I’m not sure the board has done all the fundraising it can do.

“Do some creative fundraising. I’m worried that we’ve lost a lot of talent.”