Thanksgivingfootball has been a ratings feast for the NFL, but this year's games will have to sustain the league through some lean times.

The Walt Disney Co.'s (DIS) - Get Report ESPN is paying the National Football League $1.9 billion a year for the rights to 17 Monday Night Football games a year, the NFL Draft, the Pro Bowl, ESPN's NFL-related shows (Sunday NFL Countdown, NFL Live, Monday Night Countdown, NFL PrimeTime, NFL Matchup, NFL 32, NFL Kickoff and others), WatchESPN game simulcast rights, 3D rights, Spanish-language broadcasts and international broadcasts. However, even ESPN itself notes that NFL ratings fell 8% last year, including a 12% drop for Monday Night Football. The average viewing audience declined from 17.9 million in 2015 to 16.5 million a year later.

This year, NFL ratings have fallen 7.5% through the first six weeks of the season. Combined, that's an 18.5% decline from two years ago, but that isn't without its bright spots. Monday Night Football ratings are actually up 6% through the early weeks of the NFL season. Meanwhile, the NFL awaits its biggest regular-season ratings of the year on Thanksgiving Day.

Last Thanksgiving, 35.7 million people tuned in to Fox and watched Dallas Cowboys rookies Dak Prescott and Ezekiel Elliott eke out a win against Kirk Cousins and Washington. By comparison, only the Chicago Cubs' win in Game 7 of the World Series drew a bigger television audience (40 million) for a sporting event last fall. Earlier in the day, the Detroit Lions' narrow victory over the Minnesota Vikings drew 27.6 million viewers to CBS. NBC, however, didn't fare nearly as well thanks to the awful Indianapolis Colts (playing without injured star quarterback Andrew Luck) getting trounced by the Pittsburgh Steelers, 28-7.

The 21 million viewers who stuck around for that game was a smaller audience than NBC drew for the Macy's Thanksgiving Day Parade (25 million viewers) earlier that day. While it's still a larger audience than anything else that aired around that time of night, it's a disappointing drop considering that NBC is on the hook for $1.1 billion a year for the rights to NFL Sunday Night broadcasts, Thursday Night Football, the Thanksgiving game and Super Bowl broadcasts (including the 2018 installment) through 2021.

Even Fox and CBS have a right to be nervous about the NFL's non-Thanksgiving performance of late. Those networks pay $1 billion apiece for NFL broadcast rights through 2021, and the return on that investment is drying up. In mid-October, Credit Suisse lowered its targets for Fox and CBS shares and placed the blame on declining NFL ratings and subsequent declines in ad revenue. Broadcasters blamed protests inspired by former San Francisco 49ers quarterback Colin Kaepernick, the 2016 elections, recent concerns about the effects of concussions sustained by players, cord-cutting viewers and oversaturation of football coverage.

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In truth, the NFL is seldom able to curate its marquee Sunday Night, Monday Night and Thursday Night Football as effectively as it does its Thanksgiving games. Then again, it's being playing Thanksgiving games far longer than any of the above. The NFL's Thanksgiving slate dates back to 1934, when radio executive George A. Richards bought the Portsmouth (Ohio) Spartans a year before and moved the team to Detroit. He wasn't thrilled that his Lions were routinely second in Detroit's hearts to baseball's Tigers, so he scheduled a Thanksgiving Day matchup with the rival Chicago Bears packed University of Detroit Stadium. Though the Bears' win earned them a division championship, the next year, the Lions won the NFL Championship with a lot of help from a 14-2 win over the Bears in the Thanksgiving game.

The Lions have played on Thanksgiving since, with the only exception being the six seasons between 1939 and 1944 during World War II. The Dallas Cowboys, meanwhile, only jumped on board in 1966 -- just five years after they joined the league -- and have only sat out the holiday twice, in 1975 and 1977. Meanwhile, when the NFL wanted to promote its own network in 2006, it threw tradition in the trash and added a third Thanksgiving game. When it decided it actually wanted to make more money off of that game, it sold the rights to NBC as part of a restructured broadcast deal.

After ESPN laid off more than 100 high-profile staffers earlier this year and Turner Broadcasting (TNT and TBS) laid of 10% of its workforce after signing a $24 billion deal to broadcast National Basketball Games with ESPN two years ago, declining sports ratings can't just be shrugged off as anomalies anymore. The NFL schedules marquee matchups for Thanksgiving because it knows that's when its largest audience will be watching, and it needs to apply that strategy more broadly throughout the season.

At roughly 16 million per game, the audience is still there. However, if you want more fans to take a seat at the table on special occasions, you have to offer them more than that week's leftovers.

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