As the economy forces the broadcast nets to economize in every way possible, the deal that saved NBC’s “Friday Night Lights” from cancellation last month may be a portent of things to come for primetime skeins.

At first blush, many in the biz saw the two-season licensing agreement between NBC and DirecTV for “Friday Night Lights” as an anomaly — a Hail Mary pass for a critically beloved ensembler deemed too good to be killed off by low ratings.

But the business plan behind “Lights” could well be a model for future primetime series, as nets deal with the one-two punch of ever-rising production costs and dwindling auds, plus the left hook landed this year by the steep advertising slump.

“FNL” has essentially adapted the cable series production model to primetime — lower budgets, tighter shooting schedules, fewer episodes and a general cost-conscious mentality that fosters cheaper solutions to crane shots, crowd scenes and other expensive frills.

The show costs about $2 million and change per episode, compared to $3 million-plus for many network skeins (or just under $3 million on the low end), and there are 13 episodes per season, the norm for cable shows, rather than the network tradition of 22-24.

The “FNL” model and production mentality are looking more and more appealing to net execs as the Big Four brace for an upfront advertising sales market this summer that could be down as much as 20%-25%, by some dire forecasts. With the nets certain to take a cash flow hit, it’s very likely they’ll order fewer scripted series overall, and fewer episodes of new and returning shows.

The economic meltdown has provided the urgency, but in truth network and studio execs have been scratching their heads at how shows like AMC’s “Mad Men” and FX’s “Damages” put so much on the screen for about two-thirds the cost of a broadcast skein.

So how do they do it? A lot of it comes down to intense pre-production planning and tighter shooting skeds. With a 13-episode order, pre-production work and the writing process can run 12 weeks prior to the start of lensing, compared to about eight weeks on a network show that’s aiming to deliver 22 hours over the course of a September-May season.

The single-biggest weapon in managing costs is getting scripts in good shape well in advance of production. That allows all of the craft and tech folks — set designers, set builders, location scouts, fx mavens — to get a headstart on their tasks for each seg.

All the advance work is essential to facilitating a seven-day shooting sked, which is the norm for cable drama series compared to eight days for a network skein. That one day can add up to $2 million-$3 million in savings across a 13-episode production cycle. It also forces producers to be vigilant about getting what they need in the can each day, especially on location.

AMC’s “Mad Men,” for example, kept to a rigorous sked in its second season, shooting four days on its soundstages in downtown L.A. and three days on location for each of its episodes. But those locations tended to be close to the show’s home base at Los Angeles Center Studios, which cut down on travel time for cast and crew.

Given the scope of the period drama, production execs say they’re amazed “Mad Men’s” second season came in at about $2.5 million an episode. That was up by a few hundred grand from the first, and a princely sum by the standards of AMC and “Mad Men” producer Lionsgate TV.

On a broadcast net, the buzz generated by “Mad Men” in its first season would likely have spurred a much bigger budget for season two.

“It used to be that if a show stayed on the air, the upside was so great that it was worth the risks you took,” says Lionsgate TV chief operating officer Sandra Stern. “Today, the economics have changed. I look at some of these shows on the air and think, ‘How is anybody ever going to make money?’ ”

For “FNL,” the license fee that DirecTV pays to producer Universal Media Studios for the first window on episodes before they air on NBC covers about half of the show’s production budget, which makes “FNL” financially feasible for the Peacock even as it generates cable-level ratings. The fact that the show had to adopt a low-budget production model to survive even its first season positioned it well for the kind of creative dealmaking that NBC pursued with DirecTV.

Jason Katims, “FNL” exec producer and showrunner, cites script readiness and the show’s unusual shooting style — on high-def vid, with multiple cameras shooting 360 so there’s rarely a need for second takes or coverage — as keys to doing a champagne show on a beer budget.

For example, they’re able to double- and triple-up on all of their football game shoots — generating material for multiple episodes off of one game setup. Because the scripts are done so far in advance, producers are able to do the same with most of their location shoots.

“It saves a lot of money that all adds up,” Katims says.

And that’s the name of the game these days.