The future of NBC’s plan to shake up its late-night television lineup may depend on just how much Conan O’Brien doesn’t like what the network has done to him.

A day after NBC executives said they were contemplating a plan to move Jay Leno back to 11:35 p.m., elbowing Mr. O’Brien back a half-hour to 12:05 a.m., representatives of Mr. O’Brien’s are privately saying that he has not accepted NBC’s plan and that he is likely not to agree to it any time in the near future. But none were willing to say so publicly.

The uncertainty has created an extraordinary spectacle: Two of NBC’s biggest stars, with an aggregate salary of more than $50 million a year, and their staffs are waiting to see what might happen, with no official word being issued from the network or any of its executives.

A senior executive at a rival network said that if Mr. O’Brien and his representatives were willing to walk away from money he may still be owed by NBC, “they’ll have options.” The executive spoke on the condition of anonymity because he wanted to avoid becoming involved in NBC’s dealings with Mr. O’Brien.