by Aaron Schatz

As they say every week on the NFL Matchup show, "Football is a game of matchups." No matter how successful an NFL team is, its personnel will match up better with some opponents and not as well with others. But how do you measure this? In a season that consists of only 16 games, how can you tell how much of a loss can be blamed on random chance and how much can be blamed on the fact that your personnel just doesn't match up well with the other team's personnel? Does it help to look at games against the past opponent in recent years, even if many of the players on the field have changed? And regardless of matchup, how much does last week's game tell us about a team's current status, compared to their record from the entire season to date?

Any forecast of this week's AFC Conference Championship revolves around these questions. If we look solely at how well the New England Patriots and Baltimore Ravens played during the 2012 season, the Patriots are very obvious favorites. The Patriots weren't just miles ahead of the Ravens on offense this year; according to our DVOA ratings, they were also (slightly) better than the Ravens on defense. While the Ravens had the best special teams in the league during the regular season, the Patriots ranked fourth. On top of that, the Patriots have home field advantage and are coming off an easy win instead of a double-overtime victory which left the Ravens physically exhausted.

And yet, on the surface it sure seems that the Patriots have particular problems with the Baltimore Ravens. It's hard to argue that 2009's playoff blowout has much bearing on the game this weekend; when the Ravens stomped the Patriots 33-14, everybody on the aging Ravens defense was three years younger, and only five of the current Patriots starters were starting back then. The current phase of the Patriots organization really starts in 2010, but since then the teams have played once a year with all three games decided by a field goal or less. This year's 31-30 game from Week 3 in particular stands out because DVOA says it was the best game for the Ravens offense all season, and by far the worst game for the Patriots defense. How much does that say about this weekend's game, especially given that the Patriots will be fielding an entirely different secondary? There's also the question of what we can learn from the games played just last week. The Ravens were not expected to beat the Broncos, but they brought their best defensive performance of the year and their best offensive performance since that Patriots game four months ago. What are the odds they can keep up that level of play? For that matter, what are the odds that the Patriots will be as efficient on offense as they were against Houston? And how likely is it that either team revisits the kick coverage problems they showed a week ago?

To figure this all out, we'll want to look at each team's numbers for the entire season, their trends over the past few weeks (far more important than just the last single game), and what matchup issues from Week 3 might remain four months later.

For those who may be unfamiliar with the Football Outsiders stats, they are explained at the bottom of the page. Scroll down or click this link. Please remember that all stats represent regular season only, except for weighted DVOA and anything else specifically noted.

Any game charting data that appears with an asterisk appears courtesy of the ESPN Stats & Information Group and is complete through the end of the season. All FO game charting data is now complete for the four remaining playoff teams.

Ravens on Offense BAL OFF NE DEF DVOA 3.0% (13) 1.3% (15) WEI DVOA 3.9% (13) -3.0% (12) PASS 9.6% (15) 13.9% (23) RUSH 7.5% (7) -16.0% (6) RED ZONE -6.1% (19) -6.8% (9) Patriots on Offense NE OFF BAL DEF DVOA 30.8% (1) 2.2% (19) WEI DVOA 34.0% (1) -5.6% (10) PASS 53.8% (1) 3.4% (13) RUSH 11.9% (4) 0.9% (26) RED ZONE 34.5% (3) -10.4% (8) Special Teams BAL NE DVOA 9.0% (1) 5.5% (4) BAL kickoff +12.4 (3) +2.2 (11) NE kickoff +13.3 (3) +15.0 (1) BAL punts +7.4 (10) +5.9 (5) NE punts +2.5 (9) +6.2 (11) FG/XP +9.4 (3) -1.8 (18)

All readers can click here for in-game discussion on our message boards. If you have FO Premium, you can click here to see all the matchup of DVOA splits for this game. Don't forget to also check out our scouting preview in Andy Benoit's Film Room

WHEN THE RAVENS HAVE THE BALL

This is where the questions about the AFC Championship really reside. On the other side of the ball, we know that the Patriots have the best offense in the league while the Ravens have consistently been an average or slightly above-average defense except for a two-week stretch in October against Dallas and Houston. But on this side of the ball... who knows? This, despite the absence of Rob Gronkowski for the rest of the playoffs, is where the Patriots personnel looks much different than it did in Week 3. This is where the Patriots seem to have weaknesses that the Ravens can exploit -- unless the personnel changes have solved those problems. And most importantly, this is where the Ravens are extremely inconsistent. Baltimore relies heavily on the deep ball, and deep ball offenses are often inconsistent. Baltimore ranked 30th in offensive consistency this year, based on game-by-game offensive DVOA. They were 26th last year. Consistency is usually considered a good thing, but when you go into a game as the inferior team trying to score an upset, it's better to be inconsistent. If each team comes out and has their average performance on Sunday, the Ravens will lose by two touchdowns. Inconsistency means that Joe Flacco put up a 3.2 yards per pass, two-interception craptacular like he did against Houston back in Week 7. But it also means that the Ravens could have one of those days where everything clicks, where Ray Rice is gaining five yards per carry and all those deep passes all fall right into the hands of the receivers (and then don't bounce off those hands, especially if the receiver in question is Jacoby Jones).

The Ravens had a game like that the first time they played the Patriots. Of course, the fact that they still needed a last-second field goal to win that game despite a dominating offensive performance doesn't necessarily bode well for their chances this weekend.

The deep ball is generally acknowledged to be the big weakness of the Patriots' defense, but it's a lot less of a weakness since the midseason changes that put Aqib Talib and Alfonzo Dennard into the starting lineup at cornerback while moving Devin McCourty to safety. In fact, it may have been overstated to begin with. The Patriots led the league, allowing 79 different pass plays of 20 or more yards this year (including DPI calls). However, only 40 of those plays were actually passes that went 20 or more yards through the air. Six of them actually started as passes thrown behind the line of scrimmage.

Forty bombs of at least 20 yards is still a lot, but again, that's changed significantly since midseason. If you split the season in half, you can really see the difference. (The second line includes two games where Talib and Dennard were hurt, but also includes the playoff game against Houston where they returned to the lineup.)

Patriots Defense on Passes over 20 Air Yards, 2012 Weeks DVOA Passes Yds Avg C% DPI INT TD Weeks 1-10 45.2% 59 915 15.5 46% 3 6 7 Weeks 11-19 -3.1% 40 413 10.3 32% 3 4 5 Numbers (except completion rate) include DPI.

The improvement has been particularly strong in the deep middle of the field, where Devin McCourty now roams. Since Week 11, including last week's playoff game, opponents have completed just 3 of 13 pass attempts to the deep middle of the field, with one very long DPI gain (40 yards by Andrew Luck to Donnie Avery) and four interceptions.

Joe Flacco's strengths and weaknesses will really force Aqib Talib into the spotlight for this week's game. After Talib's arrival, Bill Belichick occasionally went away from his usual strategy of leaving the cornerbacks on specific sides; last week, for example, Talib basically covered Andre Johnson wherever he was. For the most part, however, Talib is on the offensive right and Dennard is on the left. This is where we run the same table we've run the last two weeks, which shows just how dramatically better Flacco is throwing to his right or up the middle:

Joe Flacco Passes by Direction, 2012 (includes DPI) Direction Passes C% Yd/Play DVOA left 183 49% 5.1 -22.1% middle 116 69% 9.7 57.1% right 241 63% 7.8 30.1%

The game charting stats actually show Dennard with better numbers than Talib, although we haven't made any adjustments yet for the quality of receivers each defender was covering. Based on current data, Dennard has a 57 percent Success Rate and 7.4 yards allowed per pass, while Talib has just 38 percent Success Rate and 9.3 yards allowed per pass. Last week, Talib had a hard time shutting down Andre Johnson, but then again, who doesn't? He did do a good job of preventing Johnson from getting yards after the catch.

The addition of Talib also let the Patriots move Kyle Arrington to the slot, where he is a much better fit. Our charting numbers give Arrington 13.2 yards allowed per pass with 30 percent Success Rate through Week 10, which would be the worst numbers for any corner in the league over the course of a full season. In Weeks 11-15, Arrington allowed 4.4 yards per pass with 73 percent Success Rate. (Arrington was back outside in the final two weeks due to Dennard's injury.)

One of the other changes the Patriots made around midseason was an increase in blitzes. In their first eight games, the Patriots blitzed on 16.6 percent of pass plays, and sent a big blitz (six or more) only 2.5 percent of the time.* Since Week 10, the Patriots have blitzed on 32.0 percent of pass plays, sending a big blitz 7.9 percent of the time. The Patriots' defense got stronger by sending more pass pressure: 7.1 yards per play with four pass rushers, 6.5 with five pass rushers, and 5.9 with six or more. Sending extra pressure will be even more important this week if rookie Chandler Jones is out or limited due to injury. For the record, however, Flacco didn't show much of a difference this year no matter how many pass rushers you sent at him.

With the improved pass pressure and the changes in the lineup, the Patriots' pass defense improved after midseason against all five of the types of receivers that we track. Nonetheless, they've had a weakness against tight ends all season long. In the Week 3 game, Dennis Pitta had five catches on seven targets, for 50 yards and a touchdown. (Ed Dickson, however, caught just two passes for five yards.) The Patriots' current defensive scheme also seems to leave big holes on the sides for opponents to throw to running backs in the flat. Those plays were open all game for Houston last week, and in Week 3, Ray Rice had catches of 12 and 27 yards.

It will be interesting to see if those holes make it easier for the Ravens to convert shorter third downs. For the season, the Ravens were just 21st in pass offense DVOA on third downs, primarily because they couldn't connect in situations with just 1-6 yards to go. On third-and-long, however, the Ravens ranked fourth in offensive DVOA. The Patriots defense was only 20th against opponents on third-and-long.

Normally, I emphasize that teams don't run enough on third-and-short, but in this matchup, short passes are the way to go for the Ravens. The Patriots were 25th on defense on third-and-short precisely because they couldn't stop short passes in that situation. They were excellent against runs, allowing just 50 percent conversion in Power situations, second in the NFL. The Ravens also need to figure out why their running game declined so much in the second half of the season. These numbers suggest that Ray Rice is a lot more likely to make a big play with a catch than with a carry:

Ravens Running Game, 2012: Before and After Bye Week Weeks DVOA Rk ALY Rk Stuff% Rk Weeks 1-7 22.5% 2 4.67 2 12% 1 Weeks 9-17 -0.7% 15 4.15 13 19% 15

The Patriots were quite susceptible to outside runs, ranking just 30th in Adjusted Line Yards against runs around right end, and 31st against runs around left end. Overall, the Ravens are better running up the middle or to the right than they are running left, so perhaps right end is the way to go if they want a big gain.

One more important split here is in the red zone. The Patriots defense generally bucks the usual regression and is better in the red zone year after year, and this year was no exception. When it comes to the red zone, the Ravens were fourth running the ball and 28th passing the ball, perhaps because the threat of the deep ball is gone.

WHEN THE PATRIOTS HAVE THE BALL

If the Ravens offense vs. Patriots defense matchup is like a box of chocolates, then this side of the ball is more like a box of Cracker Jack. For the most part, you know what you're going to get. You're going to eat it all really fast and it's going to be pretty tasty. To provide just a little bit of mystery, there will also be a toy surprise. What could it be? An 80-yard screen pass to Shane Vereen? Michael Hoomanuwanui darting up the seam for a touchdown catch? Aaron Hernandez rushing for 50 yards out of the backfield? Maybe it will be 137 temporary tattoos you can apply to your own arms to help you look like Aaron Hernandez rushing for 50 yards out of the backfield.

Ironically, perhaps, this is also the side of the ball with the most change since the previous meeting. Hernandez and Vereen are in for the Patriots, while Rob Gronkowski is sidelined. The Ravens are without their best cornerback, Lardarius Webb, but they have Terrell Suggs back. Suggs is one of the numerous Ravens defenders who is still dealing with the effects of injury, but most of those players have been moved up to Probable on this week's injury report, so the Ravens defense appears to be healthier than it has been in quite a while.

Suggs only had two sacks during the regular season, but whether he was the catalyst or not, the Ravens' pass rush definitely improved over the course of the season. The Ravens' Adjusted Sack Rate went from 5.2 percent before their Week 8 bye to 8.2 percent afterwards. If we want to look at that split as Suggs active/Suggs out, it becomes 5.7 percent with Suggs out (Weeks 1-6 plus Weeks 14 and 17) and 7.9 percent with Suggs in the lineup. It's hard to take down Tom Brady because he usually gets rid of the ball very quickly, as evidenced by the Patriots finishing fifth with just 4.5 Adjusted Sack Rate on offense, but every little bit of pass rush helps.

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The Ravens will surely gameplan to stop the Patriots' most dangerous weapons, Wes Welker and Aaron Hernandez. The Ravens' "defense vs. types of receivers" numbers suggest that Welker would be a huge problem, because Baltimore is 30th in the league against No. 2 receivers. However, the more important matchup here is which cornerback covers Welker, because he's usually in the slot. Since Webb's injury, Corey Graham has been covering slot receivers, and he's been very good. The numbers we have so far give Graham a 62 percent Success Rate, 11th in the NFL among corners with at least 35 charted targets. He's allowed 5.8 yards per pass, which ranks 16th.

It will be interesting to see how the Ravens cover Hernandez, and whether it changes depending on whether he's wide, in the slot, or in the backfield. The Ravens were ninth in defense against tight ends and seventh against running backs as receivers. However, as Vince Verhei pointed out in this week's Quick Reads, Ray Lewis has improved Baltimore's run defense but hurt their defense against running backs as receivers. Brady will be licking his chops if he somehow ends up with Lewis in man coverage on Aaron Hernandez.

If the Patriots want to concentrate on attacking Baltimore's weaknesses rather than concentrating on what they themselves do well, that means two things: passes to Brandon Lloyd, and a big dose of the ground game. Once again, we get into the question of how much we can learn from that Week 3 game compared to the season as a whole, because in Week 3, one of those weaknesses was a problem for Baltimore and one was definitely not.

Over the last few games, the Ravens have settled on a lineup that has Cary Williams covering the offensive left and Chykie Brown the offensive right, with Graham in the slot. We don't have that many charted targets to go on with Brown, but Williams has been awful. Williams has 43 percent success rate (82nd) and 7.8 yards per pass (59th). Looking at our charting for the Week 3 game is not very encouraging if the Ravens are counting on Williams to stop anything on Sunday. We have Williams listed in coverage on 14 passes in that game: nine to Brandon Lloyd, two to Julian Edelman, two to Wes Welker, and one to Deion Branch. Tom Brady completed 10 out of those 14 passes for 113 yards. Out of the four incomplete passes, one was overthrown, one was underthrown, and the other two were defensed -- but by Ed Reed, not by Williams. But hey, at least Williams didn't allow any touchdowns.

The ground game didn't work quite as well for the Patriots the first time around. Danny Woodhead, Stevan Ridley, and Brandon Bolden combined for just 75 yards on 30 carries. However, this was Baltimore's best day on run defense all season. For the most part, the Ravens were awful against the run all season, and the Patriots were much better than they were in Week 3.

As I explained in an ESPN Insider piece this week, the Patriots' running game this year really wasn't much better than it was last year. There was just more of it, in large part because their hurry-up offense meant there was more of everything. One reason the Patriots run so effectively, of course, is that defenses are often planning against the pass, even when the Patriots are in non-shotgun sets with just two wide receivers on the field. One of the neat new statistics we have this year thanks to teaming up with ESPN Stats & Information for game charting is a record of how many defenders lined up in the box on each play. From that, we know that the Patriots faced a depleted box with just six or fewer defenders on 54 percent of all runs (not counting scrambles).* This ranked fifth in the NFL; the league average was 33 percent. The Patriots averaged 4.8 yards per carry on these plays with only six in the box, which was no better than average. The NFL average with six or fewer in the box was 4.8 yards per carry, compared to 4.3 yards per carry with seven and 3.4 yards per carry with eight.

On the other hand, a long run of fine Ravens run defense ended in 2012. From 1997 through 2011, the Ravens ranked in the top eight for run defense DVOA every single season except for 2002, when they ranked 11th. This year, they fell all the way to 26th. The defense didn't seem so bad on the surface -- 4.10 yards per carry by running backs was still 13th in the league -- because the Ravens were allowing consistent gains but not a lot of big breakaway highlight runs. They stuffed runners only 14 percent of the time, last in the league, and they allowed opposing running backs a Success Rate of 52 percent, also dead last.

The Ravens also couldn't stop the run in the most important situations. The Ravens ranked 24th in DVOA run defense in the red zone (New England was fifth on offense). The Ravens ranked 28th in DVOA run defense on third down (New England led the league on offense). If we include quarterback sneaks as well as running back carries, the Ravens allowed opponents to convert 76 percent of Power runs, which was 29th in the league. The Patriots' running backs weren't particularly great at converting those runs, but of course Tom Brady runs the best quarterback sneak in the NFL. He converted all seven of his runs in short-yardage situations.

Those stats in the most important situations really contrast with how well the Ravens defended the pass in the same situation. They were fourth in defense against red-zone passes, and second in defense against third-down passes. (The Patriots' passing game was third and first, respectively.)

So, what happened in that Week 3 game that made it so different? Our game charter summarized the problem as "Ryan Wendell getting owned by Haloti Ngata," but Courtney Upshaw and Pernell McPhee (who is not known for being particularly strong against the run) also did a good job sealing the edge. There were also a couple of plays where the Ravens defensive backs just flew into the backfield at the snap.

However, Wendell is a fourth-year project player who became a regular starter for the first time this season, and he clearly improved over the course of the year. Between sacks, hurries, and runs for loss, our charters marked Wendell with nine specific blown blocks through the Patriots' first seven games. In their last nine games, we marked him with just 4.5 blown blocks. (I'll note here that we're not asking charters to analyze every block on every play, so it isn't like all of Wendell's blocks are perfect. We ask them to mark when specific blown blocks stand out as blowing up the play. By that measure, and by the subjective opinion of pretty much everyone who covers the Patriots, Wendell improved significantly in the second half of the season.) Wendell wasn't the only lineman who played better later in the year, as the Patriots went from 4.33 Adjusted Line Yards per carry before their bye week to 4.55 ALY after the bye (which would have led the league over the whole season).

Run defense is where the return of Lewis is good news for the Ravens -- well, run defense and locker-room motivational speeches. With Lewis in the lineup, the Ravens' run defense DVOA has gone frrom 4.6% to -5.0%, which would have ranked 18th for the season instead of 26th. Lewis has looked reborn against the run the last two weeks, and the Broncos could barely get three yards per carry against Baltimore. However, the Patriots have more talent than the Broncos do at running back. They won't be giving eight carries to their fourth-string back, and even if they do, Brandon Bolden is better than Jacob Hester.

The other problem with all this running is that it sets up the play-action pass, where the Patriots offense is great and the Ravens defense is awful. The Patriots gained 8.5 yards per pass with play-action, and only 6.5 yards per pass without it.* The Ravens' defense had an even bigger gap, in fact the biggest for any defense in the league: 5.4 yards per pass without play action, but 8.6 yards per pass with play action. In the first game back in Week 3, the Patriots gained 10.8 yards per play when they used a play fake, including a 59-yard connection to Wes Welker down the left sideline, early in the first quarter. (That one was on Ed Reed, not Cary Williams, as Williams had Deion Branch on the outside while Welker came out of the slot with a bit of a modified wheel route.)

SPECIAL TEAMS

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Yet again, the issue here is one game versus what we've seen over an entire season. Yes, both the Ravens and the Patriots had major lapses on kick coverage last week, but they were still two of the finest special teams units in the league this year. Each team could possibly break a big long return, but it's more likely that neither will. The only real difference between the two teams was on field goals, where Justin Tucker was excellent (he missed three field goals, all over 40 yards) and Stephen Gostkowski slumped a bit this year (he missed six field goals, including from 36 and 39 yards). Nevertheless, given Gostkowski's career history and the general inconsistency of field-goal kickers, I'm not sure there's really any difference between them.

OUTLOOK

In case you haven't had enough "one game is often different from an entire season" stats, here's another one. In Week 3, the Ravens came back from a nine-point deficit in the final five minutes. Last week, the Ravens came back to tie the game in the last 45 seconds. But over the course of the entire season, they were actually lousy in these kinds of clutch situations. In "late and close" situations (second half, within a touchdown), the Ravens were just 23rd on offense and 17th on defense. The Patriots, on the other hand, were fourth on offense and ninth on defense.

So, what does this all mean? Well, the conclusion won't shock anybody, because Football Outsiders has always argued that we learn more from long-term performance than we learn from a single game. A season is a much larger sample size to discover significant trends. As far as the specific matchups go, there's always film to help you correct or cover over whatever matchup problems you had the first time you played an opponent, and to help you attack new weaknesses.

Our playoff odds report gives New England a 69 percent chance of winning this game. With the improvement of the Patriots' defense and the decline of the Ravens' run blocking, I think the chances are a little higher, maybe 75 percent. That's not a slam dunk by any means, especially because the inconsistent Flacco could definitely go out and have a stellar performance, but either 69 percent or 75 percent is pretty darn high for a playoff game. If we look at the entire season, and not just Week 3, the Patriots are clear and obvious favorites to make their second straight Super Bowl.



STATS EXPLAINED

DVOA (Defense-adjusted Value Over Average) breaks down each play of the season and compares it to the NFL average based on situation and opponent. You'll find it explained further here. Since DVOA measures ability to score, a negative DVOA indicates a better defense and worse offense, and a positive DVOA indicates a better offense and worse defense.

SPECIAL TEAMS numbers are different; they represent value in points of extra field position gained compared to NFL average. Field goal rating represents points scored compared to average kicker at same distances. All special teams numbers are adjusted by weather and altitude; the total is then translated into DVOA so it can be compared to offense and defense. Those numbers are explained here.

Each team is listed with DVOA for offense and defense, total along with rush and pass, and rank among the 32 teams in parentheses. (If the DVOA values are difficult to understand, it is easy to just look at the ranks.) We also list red zone DVOA and WEIGHTED DVOA (WEI DVOA), which is based on a formula which drops the value of games early in the season to get a better idea of how teams are playing now (explained here).

Each team also gets a chart showing their performance this year, game-by-game, according to total DVOA. There are separate charts for offense and defense. In addition to a line showing each game, another line shows the team's trend for the season, using a rolling average of the last five games.