The National Football League season just kicked off one week ago, and the frontrunners to make the Super Bowl haven’t even been determined yet. But NBC is already nearly sold out of inventory for the big game.

The network, airing the game for the first time since 1998, said yesterday that it has moved 85 percent of its inventory for the game, an unusually high level for this time of year. Usually networks have sold off about half of inventory by this point.

There are 10 30-second spots left to be sold, according to The Wall Street Journal, which first reported the story. Many of the ads have been snapped up by returning advertisers such as Pepsi, Anheuser-Busch and Careerbuilder.com.

NBC has been hyping the Super Bowl practically since the last game finished its record-breaking airing on Fox last year, becoming the most-watched ever with nearly 98 million total viewers.

At NBC’s pre-upfront presentation, the network emphasized the game as a big part of its strategy for the new season, planning to launch a new show out of the Super Bowl and promoting its playoff tie-ins earlier in the year.

NBC is also coming off a major sports triumph with August’s Olympics, which drew the biggest cumulative audience, 211 million viewers, for any Games in history. In an era of sinking ratings, Beijing was up over the past two Olympics, a feat that many have credited to the network’s slick production and smart scheduling.

So it’s probably no surprise that the network, which worked closely with advertisers in developing its fall slate, has been selling so aggressively.

Prices for a 30-second spot are said to be hovering at a high of $3 million, up from the average $2.7 million Fox received last year. But advertisers who buy more time in the game, like Anheuser-Busch, annually the game’s top spot buyer, get price breaks of roughly $1 million per ad.

Not all past advertisers are clamoring to be part of the Super Bowl in this poor economic climate, however. General Motors recently announced that it was slashing its advertising budget after a couple rough years, and the car maker already has pulled out of February’s Academy Awards on ABC.

It will sit out the Super Bowl too, according to The Journal, though it will air ads before and after the game.

Another reason for the intense interest in the Super Bowl, and sporting events in general, is the continued rise of digital video recorders, now in 27 percent of Nielsen households. Advertisers with a time element to their ads, promoting a new launch, for example, or a limited-time promotion, prefer to connect with viewers in real time.

Sporting events represent the least-time-shifted programming on television, as most fans want to watch the game in real time rather than risk being told of the outcome before getting a chance to watch the tape.