The Houston Texans and Baltimore Ravens, meanwhile, picked the wrong time of year to suffer the statistical chills. These two teams need a dramatic change of fortunes to return to the contender status they enjoyed at various times earlier in the season.
Newtonian physics tells us that the greater the momentum of an object, the greater the force it takes to stop it. Put another way, it takes a lot more effort to beat a red-hot football team.
The laws of football physics are not quite as exact as the laws of nature, of course. After all, teams are something more complex and organic than an inanimate object hurling through space. The various motivations and foibles of flawed humans, not to mention the odd and seemingly random bounces of an oblate spheroid, can impact outcomes in ways that the laws of nature cannot easily predict.
But it's still an interesting if inexact exercise to gauge momentum in the NFL -- who's hot and who's not entering the playoffs -- and then determine if it even matters.
The 2012 postseason provides a perfect case study in momentum: an interesting mix of teams, some great and some mediocre, that are either peaking at the right time or falling apart at the wrong time. Each of the 12 playoff contenders has a fairly distinct statistical storyline that tells us who's hot and who's not entering the postseason.
There are many methods we can use to test momentum entering the playoffs. The most obvious, of course, and the most important, is wins and losses: the hands-down winner in that case, of course, is Denver. Peyton Manning's mile-high crew powers into the postseason with 11 straight victories.
The method we prefer to use to gauge a team's statistical momentum is Passer Rating Differential -- that's the difference between your Offensive Passer Rating and your Defensive Passer Rating (the formula for quarterbacks applied to pass defense).
Passer Rating and Defensive Passer Rating alone are fairly telling indicators of team success. Highly efficient quarterbacks win a lot of games. Defenses that make opponents highly inefficient win a lot of games, too.
Subtract one from the other and you have Passer Rating Differential, or what we call the Mother of All Stats because it's so deadly accurate at separating winners from losers and champs from chumps, and has been through all of NFL history.
You win more than 80 percent of all NFL games when your quarterback posts a higher passer rating than the opposing quarterback. In fact, teams that won the battle of Passer Rating Differential in 2012 went 209-46 (.820). For the sake of comparison, teams that passed for more yards went just 127-125 (.504).
More importantly, you win championships when you dominate Passer Rating Differential: 36 percent of all NFL champions since 1940 finished the year No. 1 in Passer Rating Differential.
That's pretty amazing: if you looked only at Passer Rating Differential and nothing else, you could pick the champion out of a lineup of all NFL teams in better than 1 in 3 seasons since 1940.
More than 60 percent of NFL champions finished in the top 3 in PRD. That's good news for this year's top three: Green Bay (+31.5), Seattle (+28.8) and Denver (+25.9).
Here's a look at the relative statistical heat of each Super Bowl contender entering the postseason.
Status: Struggling to get up off the statistical mat; W-L streak: one loss Passer Rating Differential: Peak (Week 2, +63.8); Trough (Week 12, +13.8); Final (5th, +22.0)
Momentum overview: The Falcons raced out of the gates in 2012, peaking statistically after their 40-24 Week 1 domination of the lowly Chiefs. They maintained a +55.9 PRD entering Week 4. It's been steadily downhill for the Falcons since then.
Atlanta bottomed out heading into the Tampa game in Week 12, after narrowly edging out the struggling Cardinals in Week 11. Matt Ryan and the gang have regained some momentum here at the end of the season (+22.0), but they are still playing far below their lofty early season standards entering the postseason. The Falcons need to pick up the pace.
Status: Bouncing off the bottom; W-L streak: one loss Passer Rating Differential: Peak (Week 2, +60.4); Trough (Week 9, +2.6); Final (12th, +5.8)
Momentum overview: Chesapeake Bay striper fishermen know that you can often catch the prize bass by bouncing your bait off the bottom of the sea near rocky outcrops. That method more or less describes Baltimore's performance here down the stretch: the Ravens are bouncing along the statistical bottom of their season.
The Ravens peaked early, very early, with their Week 1 44-13 win over the Bengals -- the victory that caused everyone, if only for a moment, to name Joe Flacco the NFL's elite young QB du jour. Baltimore hit rock bottom mid-season (+2.64 PRD) and has barely regained momentum entering its wild-card game (+5.78) -- not a good sign as they prepare to host the surging Colts.
Status: Warm and getting warmer at just the right time; W-L streak: three wins Passer Rating Differential: Peak (Week 16, +7.32); Trough (Week 2, -60.4); Final (11th, +7.26)
Momentum overview: The Bengals were humiliated 44-13 by the Ravens in Week 1 and entered Week 2 in a -60.4 hole in Passer Rating Differential. But they have slowly climbed out of that abyss week by week, before finally picking up steam here late in the season.
Cincinnati has gone 7-1 over the second half of the season and has been consistently good, but not great in PRD, since Week 13. They're a team that's still only slightly above average -- but playing as well as they have all year, closing out the season just 0.6 points shy of its season high in PRD.
Status: Simmering hot and steady; W-L streak: 11 wins Passer Rating Differential: Peak (year end, +25.9); Trough (Week 4, -13.0); Final (3rd, +25.9)
Momentum overview: The Broncos bottomed out way back in Week 3, after consecutive losses to the Falcons and Texans. They quickly recovered with a 37-6 destruction of the Raiders and continued moving forward despite a 31-21 loss at New England in Week 5 -- Denver's last loss of the season, way back on Columbus Day weekend.
Since midseason, the Broncos have steamed forward as steadily and unstoppably as any team in football, consistently around +25 in Passer Rating Differential and peaking at just the right time with their highest number of the year entering the playoffs. Denver is very strong on both offense and defense and, right now, playing its best ball of the season. It's a scary good combination.
Green Bay (11-5)
Status: Consistently hot championship form; W-L streak: one loss Passer Rating Differential: Peak (Week 12, +32.0); Trough (Week 2, -32.4); Final (1st, +31.5)
Momentum overview: Green Bay is the NFL's reigning Passer Rating Differential dynasty. They finished No. 1 in 2010, riding that dominance of the skies to a Super Bowl title; they finished No. 1 again in 2011, posting a franchise-best 15-1 record before falling apart on both sides of the ball against the Giants in the playoffs; they're No. 1 again here in 2012.
The Packers stumbled out of the gate with their 30-22 loss to the 49ers">49ers in Week 1, a game in which San Francisco dominated the passer rating battle (+32.4). The Pack quickly recovered and, since beating up Houston in Week 6, has consistently led the NFL in PRD.
They are dominant in this number, but not necessarily hot.
Green Bay proves the power of Passer Rating Differential through years, that you win when you dominate through the air. Just ask Vince Lombardi's Packers. They finished No. 1 in PRD in 1961, 1962, 1965 and 1966 and won NFL titles each year. They were No. 3 in 1967, before turning it on in the playoffs (+42.5 PRD in three games) and winning yet another NFL title and Super Bowl.
Status: We have a statistical problem; W-L streak: two losses Passer Rating Differential: Peak (Week 2, +63.4); Trough (Week 7, +8.2); Final (8th, +9.3)
Momentum overview: No team enters the 2012 postseason with less momentum than the Texans. They raced out of the gates with a 30-10 win over the Dolphins -- dominating the PRD battle by 63.4 points -- and have grown steadily worse since that day.
Houston statistically bottomed out entering Week 7, after the crushing 42-24 home loss to Green Bay that exposed all the flaws in what appeared to be a Super Bowl contender. It the Texans were the Titanic, the Green Bay game was the moment they hit the iceberg.
Houston has taken on statistical water since that game and enters the playoffs just a point above their season low in Passer Rating Differential.
Status: Cold but getting lukewarm at just the right time; W-L streak: two wins Passer Rating Differential: Peak (year end, -13.7); Trough (Week 2, -46.0); Final (27th, -13.7)
Momentum overview: Every so often there's a team that defies the odds and reaches the playoffs with the statistical profile of a loser. Denver was that team last year (No. 28 in PRD). The Colts are that team this year: No. 27 in PRD.
Indy has been negative in PRD all season and still is today. Andrew Luck has put up big volume numbers, but has been largely inefficient thanks to a low completion percentage and high number of turnovers (remember, even Peyton Manning threw 28 picks as a rookie).
The season started ugly, too, with a 41-21 loss to the Bears. But the Colts have displayed plenty of moxie over the course of the season: slowly getting better each and every week. Indy has never been better than it is today -- but that's still only lukewarm at best. The postseason won't last long. But the future looks very bright.
Status: Getting warmer but the wrong team in any era; W-L streak: four wins Passer Rating Differential: Peak (Week 6, +10.9); Trough (Week 14, -13.6); Final (24th, -11.1)
Momentum overview: The Vikings enter their wild-card game at Green Bay on a four-game win streak -- and yet are statistically incapable of making a deep run into the playoffs.
Adrian Peterson is fresh off one of the best seasons by a running back in NFL history, with 2,097 rushing yards and a Jim Brown-esque 6.0 YPA. But the reality is that running backs, even the greatest, never carry teams to championships alone. They need the help of a strong passing game. And the Vikings don't have one.
In the passing game, where it matters most, the Vikings are deficient on both sides of the ball. They join the Colts as the only playoff teams under water in Passer Rating Differential. Only two teams since 1940 have been negative in PRD and won a championship: the 1957 Lions (-4.5) and 2007 Giants (-10.4). The Vikings are fighting against the weight of history, even with Peterson.
New England (12-4)
Status: Hot but ready to short-circuit at any time; W-L streak: two wins Passer Rating Differential: Peak (Week 2, +34.4); Trough (Week 7, -3.7); Final (7th, +10.7)
Momentum overview: The Patriots raced out of the gates, dominating the lowly Titans 34-13 (and +34.4 in PRD) in Week 1. They quickly fell back to earth with losses in three of their next five games and statistically bottomed out in the wake of their 24-23 loss at Seattle.
Tom Brady's Bunch pulled it back together with a 9-1 record in their final 10 and has largely been on the upswing, gaining momentum here when it matters most late in the year.
But it's been decidedly imbalanced: the No. 3 scoring offense in history (557 points) was powered by an elite passing attack, but the team as a whole was weighed down by a merely average defense (No. 17 in Defensive Passer Rating).
New England is hot enough to win it all and has a passing game good enough to win it all. But the Patriots could easily short-circuit as the most imbalanced team in the playoff field.
San Francisco (11-4-1)
Status: Warm and too erratic for comfort; W-L streak: one win Passer Rating Differential: Peak (Week 2, +32.4); Trough (Week 4, +13.1); Final (4th, +23.2)
Momentum overview: San Francisco's strong, but frustratingly inconsistent season is easy to see through the prism of Passer Rating Differential.
The 49ers won 11 games, enjoy a first-round bye and they are a threat to beat anybody. Yet they've failed to win more than two games in a row this year: big wins over teams like Green Bay, Seattle and Chicago were punctuated by bad losses to the Giants and Seahawks, and by a 0-1-1 record in two overtime games against the second-rate Rams (7-8-1).
Jim Harbaugh's bold move to bench Alex Smith and start untested Colin Kaepernick has not yet paid off, at least if you value the power of Passer Rating Differential: Kaepernick's rating is 6 points lower than Smith's. The 49ers ranked No. 2 in PRD (+29.0) with Smith still the starter. They end the season No. 4 (+23.2).
Bottom line: Kaepernick has not yet paid off in any meaningful statistical way.
Status: Red hot and boiling over; W-L streak: five wins Passer Rating Differential: Peak (Year End, +28.8); Trough (Week 2, -8.5); Final (2nd, +28.8)
Momentum overview: If momentum truly has value in the NFL playoffs, Seattle is in very, very good shape. No team is hotter. No team is rising faster.
Seattle's Passer Rating Differential chart shows the greatest upward trajectory of any 2012 playoff contender.
The Seahawks literally started with their worst game of the season, a 20-16 loss to the Cardinals that now seems hard to comprehend in retrospect given the condition of each team at the end of the year. They slowly got their feet under them with a controversial win over Green Bay in Week 3 and a narrow win over the dynastic Patriots in Week 6.
It's all rolled their way since then, punctuated by five straight wins to end the season, including an incredible 150 points scored in Weeks 14, 15 and 16. Seattle is hugely balanced on both sides of the ball: rookie Russell Wilson has powered a unit that is No. 5 in Offensive Passer Rating (100.6) and it's paired with a unit that's No. 3 in Defensive Passer Rating (71.8), the best pass defense of any playoff team.
Status: Warm, steady, ready and ultimately flawed; W-L streak: seven wins Passer Rating Differential: Peak (Week 2, +69.0); Trough (Week 11, -3.5); Final (6th, +15.1)
Momentum overview: Rookie phenom QB Robert Griffin III burst on to the scene with a dominating Week 1 performance in a 40-32 win over the Saints. His 139.9 rating that day was 69.0 points better than the great Drew Brees' 70.9 rating.
The Redskins had nowhere to go but down after that game -- but they have steadily picked up down the stretch, as evidenced by their seven-game win streak and No. 6 ranking in PRD.
But, like the Patriots, the red-hot Redskins do suffer from imbalance: Thanks to RGIII's incredible rookie season, Washington is No. 3 in Offensive Passer Rating (and No. 1 in Real QB Rating). But it is only a second-rate team on the other side of the ball: No. 18 in Defensive Passer Rating.
The Redskins have won largely in spite of their defense -- and will have to do so again to make noise in the playoffs. With that said, the team is largely playing its best ball since its Week 1 explosion here down the stretch.