It is not the Ravens, either, no matter how heartwarming this three-game turnaround has been with their rookie head coach, a rookie quarterback and a back-to-the-future defense.
All of you out there can raise your hands if you thought the Buffalo Bills would be where they are today.
How about one hand?
Like the Titans, the Bills are 4-0. Like the Ravens, the Bills have done it with a young quarterback, Trent Edwards.
But here's the difference: After finishing 7-9 a year ago and losing their last three games, the Bills have already won three times coming from behind in the fourth quarter, twice on the road, including at Jacksonville two weeks ago.
And here's another difference: Edwards, in his second year, has played as if he were the second coming of another former Stanford quarterback, a fellow named John Elway, not a late third-round pick whom the Bills drafted after dumping Willis McGahee.
I'm not saying arguments can't be made for the Titans or Ravens.
But Tennessee's only road win was at Cincinnati, and the Ravens, despite their gallant effort Monday night losing in overtime in Pittsburgh, have yet to win away from M&T; Bank Stadium.
There's also the fact that the Titans were 10-6 a season ago and made the playoffs, and while they were supposed to have Vince Young at quarterback, Kerry Collins took the New York Giants to a certain Super Bowl that Ravens fans remember well.
The Ravens and the Titans can strengthen their respective cases come Sunday when they meet. If the Ravens beat the Titans in Baltimore, that will give them three wins at home and some momentum going into Indianapolis. If the Titans win, that will improve their road resume.
But one thing won't change. The Bills, who have a bye, will still be 4-0 and still be the AFC's biggest surprise in 2008.