Thursday has been the most contentious night of the week since NBC lost its dominance three years ago, and this coming season it will be an especially squeaky-tight race among the broadcast networks.

Media buyers see ABC holding its narrow lead from last season on the strength of “Grey’s Anatomy,” but they see No. 2 CBS narrowing that lead further, its ratings boosted by the return of “Without a Trace” from Sunday night.

NBC, which saw further declines through last season, faces yet another humiliation.

Buyers think Fox, long an afterthought on Thursday, could well ease past NBC to take third place in adults 18-49 with a lineup led by the hit game show “Are You Smarter Than a 5th Grader?”

“I think ABC will hold on but CBS will be very close, and they’ll lead in total viewers because of their older profile, especially with the help of ‘Without a Trace,’” says Jordan Breslow, director of broadcast research at MediaCom.

If NBC should sink to No. 4, it will be a blow to NBC’s new entertainment president, Ben Silverman, who replaced the ousted Kevin Reilly in May and just recently stepped up with a round of schedule changes for the fall. But, to the disappointment of media buyers, Silverman did not tinker with NBC’s Thursday lineup.

NBC dominated Thursdays through the 1980s and 1990s with shows like “The Cosby Show” and “Seinfeld," only to see CBS steal it away earlier this decade. Then last season ABC came out of nowhere to take the night by moving “Grey’s Anatomy” to the 9 p.m. timeslot from Sunday. ABC’s Thursday rating surged 89 percent from 2005-'06, passing both CBS and NBC.

For the season, ABC averaged a 5.3 rating in the 18-49 demographic. CBS had a 5, down 22 percent. NBC had a 3.8, down 16 percent, and Fox had a 3 rating, up 7 percent. The CW ranked No. 6 behind Univision with a 1.5 rating.

ABC is likely to do about as well as last season or slightly better. It is keeping “Ugly Betty” and “Grey’s” on from 8 p.m. to 10 p.m. and slotting in a new drama, “Big Shots” with Dylan McDermott, at 10 p.m.

But ABC will still have a struggle on its hands.

“ABC’s 10 hour is still weak and won’t improve over last season,” predicts Susan Hajny, broadcast research manager at GSD&M. She thinks CBS could narrowly beat ABC in 18-49s for the night. “I think CBS has the strength there with ‘Without a Trace.’”

Certainly, "Trace" is key for CBS to close in on ABC, with its long-running reality show “Survivor” and cop drama “CSI” both slipping. But they believe “Trace” will lift it up, beating both  “Big Shots” and NBC’s long-fading “ER.”

NBC’s schedule, with four comedies from 8 to 10 p.m., is unchanged, beyond the flipping of "30 Rock" and "The Office," to air at 8:30 and 9.

NBC is doing its best to pump “30 Rock” with an upcoming guest appearance by Jerry Seinfeld. Working in its favor to some degree is the 10 Emmy nominations the comedy received, putting it in the league of NBC's other Thursday comedies, “My Name is Earl” and “The Office.”

But what critics think did not translate to improved ratings last season, when the network's Thursday actually declined in the second half, dropping to fourth place behind Fox. There's little reason to believe it will improve this year either.

And this season, Fox has an even stronger lineup. Its reality hit “5th Grader” returns in the fall for its first full season, airing at 8 p.m.

How Fox does at 9 is the big unknown. The new reality show “Kitchen Nightmare” is set to air this fall, starring the ever-contentious and controversial chef Gordon Ramsay, and all signs point to it doing well.

But there's a chance, slight though it may be, that the show will be delayed and even knocked off the air entirely, based on a lawsuit in which a restaurant manager featured in the series contends he was humiliated when producers made his business look worse than it really was.