Football is a tape-based analysis game, and there's no doubt the best way to get a read on teams is to break down their All-22 as much as possible.
Still, there are certain statistical trends and indicators that can be revealing in a preview sense, and here's a heaping helping of advanced numbers for the wild-card round.
These two teams are fairly evenly matched in most areas, per Football Outsiders' opponent-adjusted metrics, with one graphic exception in Kansas City's favor -- the Chiefs rank first overall in FO's special teams stats, and their return units are particularly strong. Only the Vikings ended the season with a higher total of kick return points over the league average, and no team was better in punt return points over average. Quintin Demps and Knile Davis each average more than 30 yards per kick return, and each has scored touchdowns. Dexter McCluster is the man on punt returns, scoring twice and averaging 11.8 yards per attempt. Punt return coverage is also a Kansas City strength -- they've allowed just 6.5 yards per attempt and forced 19 fair catches.
One should pause before assuming Colts quarterback Andrew Luck's numbers have suffered since receiver Reggie Wayne was lost for the season Oct. 20. While it took some time for Luck to re-jigger his targets and have everyone on the same page, he's shown he can still get it done without his best offensive teammate. Luck completed 136 of 224 passes for 1,574 yards, 10 touchdowns and three picks in the seven games, and 207 of 346 attempts for 2,248 yards, 13 touchdowns and six picks in the nine games since. His completion percentage (60.7 to 59.8) and yards per attempt (7.02 to 6.49) have gone down a bit, but nowhere near as badly as some might have you believe.
The Chiefs' defense, however ... that's been an issue of late. Bob Sutton's squad has slipped from fifth to 15th in opponent-adjusted efficiency in the second half of the season, and from second to 17th against the pass. Injuries and a lack of pass pressure have been the primary issues -- this was once the best defense in the league when it came to getting after the quarterback, and it isn't anymore. They had 35 sacks in their first seven games, and 12 in the last nine -- that's quite literally a first-to-worst proposition. Luck has been pressured quite frequently behind Indy's relatively weak offensive line, but the Chiefs only got to him once when these teams last faced off Dec. 22, and the Colts won, 23-7. Luck is using more play-action, no-huddle, and short passes to offset weaknesses in his offense, and he's done so expertly.
Because of Jamaal Charles' excellence, the Chiefs are very hard to stop on just about any kind of running play -- they rank second behind the Patriots in FO's Adjusted Line Yards metric, and they're just as effective avoiding stuffs at the line as they are getting more yards in the open field. Where this line struggles at times is in pass protection -- Alex Smith was sacked five times against the Colts, and pressured quite often. Indianapolis outside linebacker Robert Mathis had 62 total pressures to go with his league-leading 19.5 sacks, and he can bring pressure from both sides -- 189 pass rush snaps on the defensive left side, and 266 on the right. If the Colts can force Smith to check down even more than he generally wants to (and that's a lot), it will be to their distinct advantage.
Speaking of expired narratives, let's disabuse ourselves of the notion that the Eagles' defense is some sort of sieve. It was, but it isn't any more. From weeks 1 through 9, Philadelphia ranked 30th in FO's overall defensive metrics, but they've jumped up to 12th overall in weeks 10-17. And before you ask about strength of opponent, keep in mind that DVOA (FO's primary per-play metric) is adjusted for opponent. The strongest improvement has been against the run, where the Eagles have improved from 22nd to fifth. The ones who should take a bow here are defensive coordinator Billy Davis and a relatively unheralded group of defensive linemen and linebackers, starting with inside men Cedric Thornton and Fletcher Cox. And outside linebacker Trent Cole may be among the most underrated at his position -- he leads his team with 42 overall stops. On Saturday, he'll be facing off against Saints left tackle Terron Armstead, who's been less than effective in his first two starts. Drew Brees may be running a lot more than he'd like, and for all the wrong reasons.
And while New Orleans' defense has been excellent all year despite some key injuries -- a testament to the excellent job Rob Ryan's done in his first season there -- Philly's offense looks about as formidable as any in the league ... especially recently. The Eagles rank first in Rushing DVOA for the full season, they're fourth in Passing DVOA since Week 10 (when Nick Foles really got rolling), and they're first overall in total offensive DVOA in the season's second half. As several Super Bowls have been won in the last decade by the team that got hot at just the right time, Philly's trends are well worth watching.
Where the Saints have really improved in the second half of the season is in the rushing side of things -- from 28th to eighth in Rushing DVOA since Week 10. Which makes the chest injury that will keep Pierre Thomas out of this game a real blow -- Thomas led the team in carries with 147, rushing yards with 549, and only Jimmy Graham had more catches than Thomas' 77.
To add to the anxiety for Saints fans, one narrative that has legs is Drew Brees' troubles away from the friendly confines of the Superdome. He's completed 73.6 percent of his passes for 27 touchdowns and three picks at home, and 64 percent of his passes with 12 touchdowns and nine picks on the road. Brees is obviously good enough to excel anywhere, but if he's going to lead the charge and advance the Saints to the divisional round, the Eagles are going to make it very difficult for him.
San Diego Chargers at Cincinnati Bengals (Sunday, 1:05 p.m. ET)
The Chargers' defense is without question the least impressive single unit belonging to any team entering this postseason - they rank dead last overall in FO's metrics, 31st against the run, and 31st against the pass. They're also the league's worst in FO's Defensive Adjusted Line Yards metric, which seeks to specify the reasons for collapses against the run by applying value points to specific types of plays and situations. Still, when the Chargers welcomed the Bengals to Qualcomm Stadium on Dec. 1, Cincinnati was able to score just 17 points, and quarterback Andy Dalton passed for 190 yards and only one touchdown. That's a bit of a false flag, though, because the idea behind that win was to prevent San Diego's offense from going off, which they're fully capable of doing.
Chargers quarterback Philip Rivers has enjoyed perhaps his best season under new head coach Mike McCoy and offensive coordinator Ken Whisenhunt. He finished the 2013 regular season ranked behind only Peyton Manning in DYAR, FO's season-cumulative statistic, and he's behind Philly's Nick Foles in Pro Football Focus' adjusted quarterback ratings. No quarterback has been more accurate this season -- factoring out things like dropped passes and quarterback hurries, he completed over 78 percent of his attempts.
Dalton, meanwhile, ranked 11th in PFF's accuracy rankings, 14th in their adjusted ratings, and 16th in DYAR. He's coming off a 34-17 Week 17 win over the Baltimore Ravens in which he threw four interceptions on some howlingly bad reads. It was the kind of game that should put the "quarterback wins" stat to rest forever, but it is what it is. One statistical group that matters for Dalton regards his consistency -- he had an 83.2 passer rating in September, 99.1 in October, 55.9 in November, and 97.3 in December. It's good that he's trending up, but his relatively tame game against a defense this bad should give pause. Then again, maybe it was the lack of home cooking -- Dalton throws for almost a yard less per attempt on the road, his quarterback rating drops 18 points overall, and has thrown 20 touchdowns at home to just 13 on the road.
The one number nobody can account for in this game is minus-51 -- that's the projected wind-chill factor for Lambeau Field on Sunday evening, which could render a lot of the other numbers you're about to see null and void. The Packers would hope for any kind of change when facing Colin Kaepernick -- the third-year 49ers quarterback riddled their defense for a quarterback-record 181 rushing yards in last year's divisional round, and killed the Packers' secondary for 412 passing yards and three touchdowns in Week 1 of this season. More bad news -- in his last six games, Kaepernick has completed 102 of 165 passes for 1,395 yards (a whopping 8.4 yards per attempt average), 10 touchdowns, and just one interception.
If Kaepernick is able to deal with the weather and play like he has of late, Green Bay will certainly struggle to deal with it. Tramon Williams and Sam Shields, the Packers' primary cornerbacks, have each been vulnerable in coverage this season. Williams has allowed an 88-1 opposing passer rating and has allowed four touchdowns to just three interceptions. Shields has been better, but not by enough -- he's allowed a 72.7 rating, and allowed four touchdowns to four picks. Both Williams and Micah Hyde have allowed opponent passer ratings of more than 100 in the slot, which could bode well for Anquan Boldin. The veteran receiver has lined up 221 times in the slot this season, and he absolutely killed the Packers in that Week 1 game -- he caught 13 passes for 208 yards and a touchdown in his 49ers debut. Now some good news, Packers fans. In that Week 1 game, quarterback Aaron Rodgers and receiver Randall Cobb -- who each returned from injuries last week -- did a pretty nice job against San Francisco's defense. Cobb caught seven passes in 12 targets for 108 yards and a score. According to ESPN's Stats & Info, no quarterback-receiver duo have hooked up successfully on a higher number of attempts over the last three seasons with a minimum of 150 attempts. In addition, Cobb was able to burn San Francisco for multiple plays of 15 yards or more, continuing a trend from the 2012 postseason, when the 49ers allowed more throws of 15 or more yards downfield (four) than in the entire season (two).