The TV biz is bracing for movement this week in upfront advertising sales negotiations between media buyers and the major broadcast nets. The first batch of deals to emerge will go a long way toward answering the question that has hung like a dark cloud over the industry: Just how low will upfront spending go?

NBC Universal was moving toward a deal last week with buyer GroupM that called for rate declines of at least 7% for NBC in primetime, according to published reports. ABC was said to be inching closer to full-blown negotiations with buyers. CBS, Fox and CW were said to be determined to wait until this week to begin price and volume discussions with buyers for ad time in the 2009-10 season. Reps for the nets declined to comment on upfront activity on Friday.

Amid a dismal environment for ad sales in any medium, the networks face the double whammy of losing key big-spending advertisers at a time when they need every dollar they can get to amp up demand for their limited supply of spots. The bankruptcy filings of General Motors and Chrysler couldn’t have been more ill-timed for the nets, which typically book commitments for as much as 75%-80% of their ad inventory for the coming season during the first few weeks of June.

This year a quiet standoff ensued after the nets made their sked presentations to advertisers during the week of May 18. Between the recession and the general decline in network TV ratings, buyers made it clear they’re looking for big discounts — rate declines of 10%-15% — in exchange for committing their bucks in advance. Net execs have been just as determined to hold the line on cuts in the cost-per-thousand viewer rate of 2%-3% at most.

At the start of last week, it appeared that the dealmaking might not kick in until after the Fourth of July weekend. But the mating dance between buyers and sellers picked up late last week and is expected to accelerate this week, though biz insiders said the process is still likely to be much slower than usual. In flush years, upfront deals have been completed in a whirlwind three- to four-day frenzy on the heels of the sked presentations.

Media buyers say that in such an uncertain economic climate, they can’t be as free in committing billions of dollars on ad buys months in advance — even with the guaranteed prices that nets offer for upfront sales. The nets count on upfront bookings to give them a sense of what their cash flow will be for the season. If the volume and pricing of upfront sales are down dramatically, nets will hope to make up the difference in a strong scatter market, or spots sold on an as-needed basis throughout the season.

Wall Streeters and others have predicted the Big Four nets and CW will face a bloodbath of 15%-20% declines from last year’s $9.2 billion. Merrill Lynch analyst Jessica Reif Cohen predicted a 13% drop for the five nets in a report last month.

NBC appeared to be ending the impasse with its discussions with GroupM. The Peacock is facing an uphill climb in an already-difficult year, coming off a fourth-place finish in the season just wrapped. Plus, the net’s experiment with stripping “The Jay Leno Show” at 10 p.m. Monday-Friday is said to have drawn a lukewarm reaction from ad buyers so far. Cohen’s report predicted that the upfronts would see the Peacock hammered the most among the major nets, with a plunge of more than 30% from last year’s take of about $1.8 billion.

Because NBC’s circumstances are so unusual, rivals dismissed the suggestion that the Peacock’s move with GroupM would open the sales floodgates and force the other nets to agree to cut deals at discounted rates.

CBS and Fox are playing the strongest hands. CBS delivered the strongest overall perf during a rough season for the Big Four by staying essentially flat in key Nielsen measures while its competish logged declines. And CBS’ sked fortunes were bolstered by the breakout success of frosh drama “The Mentalist.”

Fox is coming off of its fifth consecutive season at No. 1 in the prized 18-49 demo thanks to the “American Idol” juggernaut. 

ABC’s upfront deals will likely be a revealing test of the overall health of the ad market and how much coin marketers are willing to commit. The Alphabet had a rocky time with its freshman shows last season, and it is gambling big on adding four new comedies and three dramas to its fall sked. 

CW, meanwhile, is hoping to get a slight boost, or at least hold the line on declines, in its average cost-per-thousand rate, now that the net is jettisoning its low-rated Sunday programming to focus on its Monday-Friday 8-10 p.m. block.