The NFL says it's just in case the Phillies make the World Series, 'cause they'd host Game 4 at 8 pm EST that night. Somehow, I don't think Fox exactly put up a huge protest over Favre vs. the Packers @ Lambeau Field being moved to the national broadcast slot.
I've heard the blackout restriction has been lifted. It will be interesting to see if the game is available everywhere or not. Last year's Dolphins/Titans game (which was also moved because of a hurricane) was only telecast in Miami and Tenessee.