With Jay Leno seemingly set to return to his old 11:30 timeslot on NBC, the network and its broadcast partners are finalizing plans to fill the weeknight 10 p.m. timeslot Leno will leave vacant.

After a 17-year run as host of the The Tonight Show, Leno was replaced by Conan O'Brien last spring when Leno moved to 10 p.m. with his new, hour-long The Jay Leno Show in September. Local affiliates were soon complaining that Leno made for a weak lead-in to the 11 p.m. news. NBC now appears ready go put Leno back into his old late-night slot and release O'Brien from his contract.

Advertisers and media buyers in the U.S. and Canada have been glued to their televisions not only to watch late night hosts spar with each other in their monologues, but to see how the schedule would shake out.

NBC announced that new and veteran NBC dramas and a comedy produced by Jerry Seinfeld will take over the bulk of the prime-time slots soon to be vacated by Leno.

The network said Thursday that the freshman drama Parenthood and the relocated Law & Order and Law & Order: Special Victim Units will fill three of the five weeknight slots.

The new lineup will debut after NBC's coverage of the Winter Olympics from Feb. 12-28.

The other new 10 p.m. show, The Marriage Ref with comedian Tom Papa and produced by Seinfeld, will air Thursdays beginning March 4. Dateline NBC will air 9-11 p.m on Fridays starting March 5.

In Canada, The Jay Leno Show airs on the Rogers-owned Citytv network and, despite middling ratings, was a boon for the network.

After acquiring City from CHUM in 2007, Rogers killed the long-running Late Great Movies from the 10 p.m. slot. Instead, they programmed a bevy of VH1 reality shows such as Glam God and Make Me a Supermodel, and comedies such as Curb Your Enthusiasm.

"We had no shows at 10 o'clock that were doing anything," said Mitch Dent, executive vice-president, television sales for Rogers. "Leno was a perfect fit... Everything before that was pretty makeshift."

The Jay Leno Show was getting approximately a 1.5 rating in the Toronto market. Numbers were just slightly lower outside Toronto. However, the stability in that timeslot allowed City to focus on its 8 p.m to 10 p.m schedule, now filled with such hits as 30 Rock, The Bachelor, Biggest Loser, Cougar Town and Modern Family.

When Leno moves in March, Citytv will shift goofy secret agent Chuck to the 10 p.m. slot on Mondays. America's Funniest Home Videos will take over Chuck's current slot at 9 p.m. on Sundays.

On Tuesday, City will simulcast Parenthood. Ugly Betty will air on Wednesdays, with two comedies–How I Met Your Mother and Accidentally on Purpose–set to run on Thursdays.

The Canadian/British co-production Murdoch Mysteries fills out the 10 p.m. schedule on Fridays.

"These are strong, big-name shows on every night," said Malcolm Dunlop, executive vice-president of programming at Rogers Media Television.

To address rumours that Conan O'Brien might find a show on an network other than NBC, Dunlop said "We've all heard so many rumours. We look at every show and... if Conan went to another network we would certainly look at it."