Ty Law leads an airtight New England pass defense into the playoffs. AP

Somewhere it is decreed by NFL canon that a playoff-bound team must finish its regular season on a roll in order to carry momentum into the postseason. The truth is, it's important, but not imperative. More times than not, the hotter team prevails in their opening game of the playoffs, but exceptions do occur.

Let's use last year as an example: In the four first-round games, the AFC held to form while the NFC didn't.

The Jets entered the playoffs having won seven of nine and three of their last four. The Colts played .500 ball in the season's final four weeks. Result? New York in a blowout.

Pittsburgh won five of its last six and three in a row before the playoffs. Cleveland somehow made the postseason despite losing three of its last five games. Unsurprisingly, it was the Steelers who moved on.

In the NFC, neither the Falcons or Packers were particularly hot. Atlanta split its final six games, losing three of its last four. Green Bay got beat 42-17 by the Jets in its regular-season finale, and went 4-2 in the season's final six weeks. When they played at Lambeau in the wild-card round, it was Atlanta that pulled the shocking upset.

The hotter team again lost in the Giants at San Francisco showdown. New York had won its last four games to make the playoffs, while the 49ers were dropping three of six and two of three to end the regular season. Still, San Francisco overcame a 24-point third-quarter deficit to pull out a miracle win.

In the four divisional games, which were hosted by the teams with the first-round byes, the home team won each game. In most cases, they were also the team that entered the game with the best late-season head of momentum.

In the AFC, Tennessee went 10-1 after its 1-4 start, and being on that kind of roll helped the Titans as they outlasted the Steelers in overtime. Oakland and the Jets were basically even in the momentum category entering their divisional playoff. The top-seeded Raiders had finished the season with seven wins in eight games, and the Jets with their playoff win had ripped off eight of 10. Oakland got the victory.

Despite losing their regular-season finale at the Giants, the Eagles finished the regular season with six wins in seven weeks. Even better, they got quarterback Donovan McNabb back for the Atlanta game, and that proved to be enough to advance past the Falcons, whose momentum really only went one game deep.

And lastly, in the other NFC semifinal, Tampa Bay thumped the 49ers, proving that San Francisco's big comeback against the Giants only had a limited effect in terms of carryover karma. The Bucs had dropped two of their final five games in the regular season, but that was enough to handle the up-and-down 49ers, who had alternated losses and wins for the previous four weeks.

Which way are the arrows pointing on the old momentum meter for this year's playoff-bound teams? Let's rate the 14 teams that are still in contention for the 12-team postseason field:

AFC

New England: It's official. Nobody in the NFL is getting it done like the Patriots, who have won 11 in a row after an injury plagued 2-2 start. New England also has the conference's most dominating homefield advantage (7-0 and the snow) and an opportunistic defense that is playing better than anyone (six touchdowns on returns).

Yes, the non-descript running game can be taken away at times. But there it was Saturday night at the Jets, putting up 133 big yards on 24 carries, with Antowain Smith (18 for 121) making like 2001. Quarterback Tom Brady has no big-play weapons, but some how he keeps on making big plays.
• Momentum rating: 10.0 on a scale of 10

Denver: Some day, when hell has just about frozen over, the Broncos will run out of running backs. Until then, Quentin Griffin, take your place alongside Terrell Davis, Mike Anderson, Olandis Gary and Clinton Portis in that assembly line of talent-laded Broncos backs. Denver out-rushed the Colts 227-47 on Sunday night, and the domination wasn't all on offense. Hang onto those MVP votes for another week, folks. Peyton Manning was a very pedestrian 12 of 23 for 146 yards and no touchdowns against the Broncos defense.

And don't look now, AFC playoff field, but Denver (10-5) has won four in a row, five of six, and hung up a combined 76 points against conference heavyweights Kansas City and Indy in recent weeks. The No. 3 seeded Colts can't be excited about the fact that the No. 6 seeded Broncos appear to be headed back to town for a first-round playoff rematch. Gulp.
• Momentum rating: 8.5

Tennessee: It's amazing what a couple big comeback wins can do for the big picture. Two weeks ago the Titans looked like a team that was going to slide into the post-season having already played their best football at mid-year, when they won six in a row. Losses to the Jets and Colts seemed to expose Tennessee as a team that could be pushed around on occasion.

But then the Titans (11-4) got off the mat to beat the Bills and Texans, and now there's still some hope that a division title and a first-round home game might be possible. In Steve McNair the Titans trust, but there's something about the entire outfit that won't allow us to dismiss their chances.
• Momentum rating: 7.5

Baltimore: When they've got their Jamal Lewis-led running game going and their suffocating defense doing its thing, the Ravens can beat anybody. But without solid quarterbacking, it's hard to see Baltimore getting on the kind of roll that could lead to a second Super Bowl berth in four years. The Ravens (9-6) have won four of five, and came up big at Cleveland when their season was on the line Sunday, but it's that ugly loss at Oakland a week ago that lingers in our mind. You never know exactly what you're going to get from Baltimore, which can lose to anyone if it turns the ball over.
• Momentum rating: 7.0

Indianapolis: By losing to the Broncos, the Colts blew a golden opportunity to earn the No. 2 seed, a first-round bye and the accompanying divisional-round home game. After being lauded for their new-found toughness after a huge win at Tennessee two weeks ago, the Colts again looked undersized and a bit, well, soft, on defense against Denver. Some times I think Tony Dungy's guys just can't stand too much prosperity.

The Colts (11-4) have still won four of their past six, but those two losses, at home to New England and Denver, has to plant a seed of doubt in their minds as to where they rank in the conference pecking order. And make no mistake, this week's game at Houston won't be a layup. If the Colts aren't careful, they could find themselves tumbling to the No. 5 seed and going the wild-card route in the playoffs. And we've seen that before.
• Momentum rating: 7.0

Kansas City: The Chiefs got a huge break when the Colts lost at home to Denver, because otherwise Kansas City probably would have stumbled into the post-season as the AFC's No. 3 seed, without the soothing effects of a first-round bye. But the Chiefs do have the first round off, and they better use it wisely to figure some things out on defense. With the Vikings gouging its defense for 223 rushing yards Saturday, Kansas City is now averaging almost 193 yards rushing allowed in its past six games.

With the Chiefs losing three times in that six-game span, after their gaudy 9-0 start, the 1972 Dolphins are probably trying to remember what all the fuss was about. Twice in the past three weeks, Kansas City's defense has been hammered for 45 points, by the Broncos and Vikings. That beep, beep, beep sound you hear is K.C.'s Super Bowl Express having been thrown into reverse.
• Momentum rating: 5.5

Cincinnati: The Bengals didn't look playoff-ready in their big game at St. Louis, but hey, nobody other than the Rams have gotten out of the EJ Dome with a win in the past 14 games. With lopsided losses to Baltimore and St. Louis in the past three weeks, the Bengals' Cinderella pumpkin carriage clearly has thrown a wheel. But with a win at home against Cleveland on Sunday, Cincy can still assure itself of a winning season for the first time since 1990 and put the pressure on the Ravens on Sunday night at home against Pittsburgh.
• Momentum rating: 5.0

NFC

St. Louis: With seven wins in a row and 11 out of 12, the Rams are starting to get that regal look about them again. Even without receiver Isaac Bruce, they handled the upstart Bengals pretty easily and have now assured themselves a first-round bye.

Yes, we know Marc Bulger can throw some interceptions, and St. Louis isn't blowing teams doors off like they did in 1999 and 2001. But the defense has a lot of impressive, young play-makers and they fly around and create turnovers, especially at home in the dome.

And maybe most importantly, head coach Mike Martz has that twinkle back in his eyes. You know the one.
• Momentum rating: 9.5

Philadelphia: Not long ago, I was almost certain I was going to get to write the following line at some point early in Super Bowl week: "Houston, the Eagles have landed.'' I thought they were a virtual lock to earn the NFC's top seed and had a great shot to turn it into a trip to Texas. But that was before the 49ers -- who had been 0-7 on the road this season -- went into The Linc on Sunday and turned back the clock to September.

Well, not exactly September, because the score would have been 31-3, San Francisco, in that case. Do I still think the Eagles can go into St. Louis and win in the NFC title game? Yep. Philly is an NFL-best 24-7 on the road since the start of the 2000 season. But are the Eagles' Super Bowl chances markedly better if the Rams do the traveling? Of course. Like the Chiefs and Colts in the AFC, the Eagles have problems on rush defense. They gave up 206 yards on the ground to the 49ers, the 11th consecutive time an opponent has reached triple figures.
• Momentum rating: 8.5

Minnesota: Any way you cut it, that butt-whipping the Vikings laid on Kansas City this weekend saved their season. Having lost six of their previous eight, the Vikings were being fitted with a different kind of horns (as in, goat) on their helmets.

But with Daunte Culpepper, Randy Moss and Onterrio Smith coming up huge against K.C., Minnesota got the biggest Week 16 momentum boost of any playoff contender. Now if they can just finish the job at Arizona, the Vikings will be a team that no one really wants to draw in the first round in the Metrodome.
• Momentum rating: 7.5

Dallas: Yeah, they beat two NFC East dregs the past two weeks to steady their sinking ship, but they did so convincingly, trouncing the Redskins and Giants by a combined 46-3. Nobody's saying the Cowboys are going far in the postseason, but let's be realistic, there are only two NFC teams that look capable of making a Super Bowl run. Somebody has to advance past the first round. Why not Dallas?

If the Cowboys can take care of the heartbroken Saints on Sunday, Bill Parcells will have produced more wins this season than any two of Dave Campo's teams. That's a real accomplishment, and could lead to a sense of real satisfaction if Big Bill doesn't keep cracking the whip with his first-time winners.
• Momentum rating: 7.0

Carolina: I know they're going to the playoffs and I know they'll have a first-round home game. But it seems like the Panthers haven't won a truly meaningful game since nipping Tampa Bay in early November. So much of what has been true for the Cowboys also applies to Carolina this season. With outstanding coaching and a limited offense, the Panthers have managed to overachieve and squeak out 10 wins, despite a shaky stint late in the season. Still, if they triumph at the Giants this week, they'll enter the postseason with a three-game winning streak.
• Momentum rating: 6.5

Seattle: In my heart of hearts, I don't even see the Seahawks earning the sixth and final NFC playoff berth. But until Green Bay plays at Oakland on Monday night, Seattle (9-6) holds the No. 6 slot. The Seahawks would have a heady little dose of momentum entering the playoffs if they win at San Francisco and get the help against Green Bay that they need.

But until further notice, Seattle's confidence reading is sky high at home, where it is a franchise-best 8-0, and rock bottom on the road, where it is 1-6 with a six-game losing streak. On average, that's not too good.
• Momentum rating: 5.0

Green Bay: Again, the Packers will vault back ahead of the Seahawks into the final NFC wild-card slot with a win at Oakland on Monday night. Even if they don't manage a victory, Green Bay can still make the playoffs, most likely as a wild card. In the best case scenario, the Packers will have a four-game winning streak heading into the postseason. If the Vikings stumble against the Cardinals, even the division title and a first-round home game are within reach.
• Momentum rating: 6.0

Don Banks covers pro football for SI.com.