Conan O'Brien, who made his debut as host of The Tonight Show on June 1, 2009, reportedly won't agree to being bumped from his current time slot by the ratings-challenged Jay Leno Show. ((Paul Drinkwater/NBC/Associated Press))

Speculation over what would happen on NBC's late night lineup continued to roil after the network indicated this week it was mulling moving The Jay Leno Show to 11:35 pm and pushing the hour-long The Tonight Show with Conan O'Brien to just after midnight.

Reports surfaced on Thursday that NBC officials were considering a shift that would put Leno back in his old slot, when he hosted The Tonight Show.

The situation got stickier over the weekend with the New York Times reporting that O'Brien representatives said the 46-year-old performer was not on board with NBC's plan and is not likely to agree to it any time in the near future.

Leno's nightly 10 p.m. show has drawn tepid ratings and reviews, weakening the audience lead-in for local late night newscasts in the U.S. Affiliates have been making their displeasure known to NBC executives.

The Times article quotes unnamed sources at rival networks, including Fox, indicating they'd welcome O'Brien. One senior Fox executive summed it up: "We love Conan."

But many network officials said they had to be cautious because they don't know details of O'Brien's contract, which could keep him at NBC. There is also a proviso that the network forfeit $40 million US to O'Brien should they take away the show from him.

O'Brien moved to Los Angeles last June to take over the chair of the iconic talk show. He had previously hosted NBC's Late Night in New York City for 17 years.

Meanwhile, O'Brien's reps have said the comedian won't be ready to make any decisions until after March 1.

Back in September, NBC Universal CEO Jeff Zucker told a business conference that the Leno experiment would be given time to find its footing.

"We're going to judge this on 52 weeks," he declared.

The Jay Leno Show has clocked in at 17 weeks now.