The relationship between Mr. Levine and Mr. Gelb has always been the subject of scrutiny and gossip, and now, as they enter into their most difficult negotiation yet, they are proceeding without the guidance or intervention of the powerful figure who influenced both: Ronald A. Wilford, the manager who closely steered Mr. Levine’s career and served as a mentor and employer to Mr. Gelb, died in June at 87.

Mr. Gelb said he would wait and see how Mr. Levine does. And the Met, attuned to the importance of public perception, took the step this month of granting The New York Times an interview at Dr. Fahn’s office to discuss with him, Mr. Gelb and Mr. Levine the conductor’s health and the deliberations over his future. Mr. Levine, who tends to keep his private life very private, indicated that he was conflicted about the idea, noting that “it’s not my nature to tell the general reader my medical problem.” But in the interview, he made it clear that he hoped to continue as music director for as long as he could do the job.

“Sometime in the foreseeable future I have to stop, but I would hope that we could decide it in a way which wasn’t rushed by the fact that I wasn’t giving them what they need,” he said at the doctor’s office. He added that he was optimistic that the new regimen, which Dr. Fahn said seemed to be yielding improvement, would allow him to continue, saying, “I want it to get, again, the way it was, because I think our collaboration isn’t finished.”

Mr. Levine’s years of health problems have left him an uncertain commodity for audiences. His first two seasons back after his spinal injury were largely free of the cancellations that had previously plagued him, and he ended last season conducting a rare doubleheader: a Saturday matinee followed by an evening performance. But his withdrawal this season from the Met’s new production of Berg’s “Lulu,” an opera that he brought into the company’s repertoire in 1977, disappointed ticket buyers and left the Met scrambling for replacements. But his transition, whenever it occurs, could put the company in a tough position. Mr. Levine, who transformed the Met’s orchestra from an uneven ensemble to one of the best in the world, is beloved by many audience members and subscribers, who see him as a link to an older, golden age of opera. He has provided reassuring continuity during a period when Mr. Gelb has often served as an agent of change, trying to bring in new audiences with more theatrically daring modern productions, more new works and popular live simulcasts of operas at movie theaters around the world.

The modern Met is, to no small degree, the House That Levine Built. After becoming music director at 32, Mr. Levine put his musical leadership and energy to work to help save the company after financial and managerial crises in the 1970s and a bitter labor dispute that canceled the beginning of the 1980-81 season. In lean years, he collaborated with John Dexter, then the director of production, on spare (and economical) but artistically distinguished productions.

In more flush times, he was in the pit for lavish spectacles by directors like Franco Zeffirelli and Otto Schenk. He championed 20th-century operas by Berg, Schoenberg and Stravinsky that had previously been rare or unknown at the Met; he became known as a Mozartian; and, by leading the company’s first complete “Ring” cycles in decades, he helped make the Met a top Wagner house. Along the way, he conducted more than 2,500 performances, more than twice as many as anyone in Met history.

“He has made this institution as great as it has been musically,” Mr. Gelb said. “He’s largely been the architect of its great international standing and success. So that certainly makes it all the more important that we support him.”