The New York Philharmonic said Sunday that it had decided to fire two key players — its principal oboist, Liang Wang, and associate principal trumpet, Matthew Muckey — for unspecified misconduct. But it said it had delayed their dismissals while the musicians’ union reviewed the matter.

The orchestra said both players had been placed on unpaid leaves of absence for now, resulting in two important holes in the ensemble’s roster as it prepares for Thursday’s gala opening night concert, which will inaugurate the Dutch conductor Jaap van Zweden’s first season as the music director of the Philharmonic.

No details of the allegations against the two players — including whether they involved sexual misconduct or not, and whether they related to on- or off-duty behavior — were provided.

The orchestra said in a terse statement only that after it had received reports that the two players had “engaged in misconduct,” it retained Barbara S. Jones, an attorney at Bracewell and a former federal judge, to investigate. An orchestra official said the investigation took five months.