MINNEAPOLIS — Management of the Minnesota Orchestra said its locked-out musicians have let a contract offer expire with no counteroffer.

The orchestra’s management said the offer expired at 5 p.m. Monday. Management said the union did not respond to the proposal offered to musicians on Sept. 14.

A union spokesman said the proposal was the same one that musicians have previously rejected by unanimous votes.

The proposal came out of a confidential mediation process. Details were not released.

Management said salary cuts and other concessions are needed to keep the orchestra solvent. Both sides are working with mediator George Mitchell.

Osmo Vanska has threatened to resign as music director if the orchestra has to cancel concerts set for November at Carnegie Hall. He has said rehearsals need to begin by next Monday.