The NFL — whose TV ratings are its biggest business as it pockets about $3.7 billion annually in network rights fees — is as flexible as a yoga master. It moved season openers to Thursdays, expanded the season with bye weeks, plays ball in London and added regular Thursday and Saturday primetime games.

Even its flexible scheduling — originally intended mainly to ensure NBC's Sunday primetime slot wasn't stuck with lame matchups — in itself seems relentlessly flexible. Tuesday, the NFL announced Brett Favre's Vikings (vs. Arizona) will replace the originally scheduled mediagenic New England vs. very respectable Miami in primetime Dec. 6 — hardly a move that simply saves NBC from a dud.

So what's up with this: Unrelenting Thanksgiving Day games in Detroit, since 1934, and Dallas, since 1966 — as if TV menus can't change over centuries.

This tradition makes as much sense as putting teams back in leather helmets every third Thursday in November. Actually, that would make more sense — who wouldn't watch?

Not that Fox and CBS' T-Day ratings are bad. They're averaging 11.5% of U.S. households over the last three Thanksgivings — above even the 10.5% ratings that the NFL is averaging in banner ratings so far this year.

Howard Katz, NFL senior vice president, says the NFL "hasn't discussed a (T-Day) change in years." And, whether that's intentional or not, the league is getting a sort of payoff from Fox's Green Bay-Detroit and CBS' Oakland-Dallas Thursday: They make the NFL Network's primetime New York Giants-Denver look like the day's best game — helping a league-owned channel so far distributed only in about half of U.S. households.