Part II of our injury series: Do some injuries become more common later in the NFL season? And has the NFL succeeded in cutting down on concussions?
16 Jan 2009
by Aaron Schatz
So, here we are again. We were here in 2003, the first year of Football Outsiders, trying to figure out if the postseason surge of the Carolina Panthers (17th in DVOA) was for real. We were here a year ago, trying to figure out if the postseason surge of the New York Giants (15th in DVOA) was for real. Now we're trying to figure out if the postseason surge of the Arizona Cardinals (20th in DVOA) is for real.
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. This year, we're going back to the old school for our in-game discussions. You can use these preview threads to discuss things before and then during each game. Just remember to switch over from NFC to AFC when the NFC game is over.
If you have FO Premium, you can click here to see all DVOA splits for this matchup.
There are a few different hypotheses that attempt to explain why Arizona is hosting the NFC Championship game.
Among the readers of this website, the most popular theory is probably the first one. In the general media, the most popular theory may be the last. There's no doubt that the Cardinals were one of the top teams in the NFL through their Week 7 bye. They didn't play quite as well after the bye, but beat their division rivals in three straight games from Week 9 to Week 11 before their performance started to dip.
The problem is that there's no real empirical evidence that can explain away Arizona's second-half collapse as "they didn't care as much." Sure, they might say some stuff to the press, but they certainly didn't look like they stopped trying. The Cardinals did not sit their starters in any way. They did not have any major injuries except for placing linebacker Clark Haggans on IR, and that doesn't matter because he hasn't been able to play in the postseason either.
Nevertheless, out of curiosity, I created a new version of DVOA that removed the games Arizona played from Week 13 to Week 16. This removes three big losses, as well as one big victory (over St. Louis). This exercise is even more interesting when you realize that it removes Philadelphia's largest win of the season. In this imaginary world where Arizona didn't play for four weeks, the final DVOA ratings look a lot different. The best team in the NFL is the New York Giants, not the Philadelphia Eagles, who are now third. Instead of being below average, the Arizona Cardinals are seventh overall in DVOA. They are a top ten team in both offense and defense, dragged down slightly by poor special teams. These numbers appear in red italics in the tables at the start of each section, except for special teams (where nothing really changed for the Cardinals in Weeks 13-16).
There's one other change this year: In the championship game previews, I've split those weekly DVOA graphs in two, separating offense and defense. Once you do this for Arizona and Philadelphia, you realize where this game will really be won or lost. Larry Fitzgerald may be the best player on the field this week, but he's less of a difference-maker than you might think.
|Full Season||Without ARI 13-16|
|ARI OFF||PHI DEF||ARI OFF||PHI DEF|
|DVOA||11.9% (10)||-20.7% (3)||20.1% (6)||-19.5% (3)|
|WEI DVOA||8.8% (13)||-24.8% (2)||17.0% (10)||-23.6% (2)|
|PASS||24.8% (7)||-22.1% (3)||37.6% (3)||-20.7% (4)|
|RUSH||-11.7% (28)||-19.1% (3)||-9.2% (29)||-18.2% (3)|
|RED ZONE||14.1% (12)||-19.8% (6)||10.2% (12)||-25.5% (5)|
Even during their late-season collapse, Arizona's offense was actually extremely consistent this year -- with one colossal exception, the week they had to play in the snow against New England. Otherwise, Arizona's only other below-average game on offense was the game against Philadelphia, and it really isn't that far below 0%.. In our imaginary world where Arizona didn't play in Weeks 13-16, the Arizona has the league's most consistent offense according to VARIANCE. In the real world, the Arizona offense ranked 21st in VARIANCE.
The Philadelphia defense has been even more consistent than the Arizona offense, particularly over the second half of the season. Philadelphia has not had a defensive DVOA over -10% in any game since their Week 7 bye. The stats for the Philadelphia defense barely change, even if we remove the Thanksgiving blowout of Arizona.
After watching Larry Fitzgerald run free in the zones between Carolina defenders, every football fan is asking the same question: "How can the Eagles can possibly stop him?" The answer is: They won't have to. All the Eagles need to do is limit Fitzgerald's production somewhat. If the Eagles can hold back the rest of the Arizona offense, a 100-yard day from Larry Fitzgerald won't kill them.
In the first meeting of these teams, the Eagles limited Fitzgerald to five catches on eight passes for 65 yards. More important, from an Eagles perspective, is that Fitzgerald made his plays against their worst cornerback, Lito Sheppard. Sheppard started the year as the nickelback but gradually lost that job to Joselio Hanson. On Thanksgiving, however, Sheppard spent most of the game on the field because the Cardinals' base offense is three-wide and starter Asante Samuel was injured. According to our game charter, Fitzgerald caught both his touchdowns as well as a 40-yard bomb while Sheppard was covering him. If Lito Sheppard is anywhere near Fitzgerald this Sunday, it will mean one of three things:
1) Double coverage with one of the better cornerbacks;
2) the Eagles have been decimated by injury; or
3) the Eagles are winning by three touchdowns.
Over the course of the season, Arizona threw 25 percent of passes to third and fourth receivers, more than any team other than the New York Giants. Arizona's "other receivers" ranked fifth among all teams in DVOA. However, Philadelphia's defense was the best in the NFC against "other receivers." In the first game between these teams, Steve Breaston and Jerheme Urban combined to catch 7 of 15 passes for just 48 yards. Breaston scored a touchdown late in the game, when he was covered by... yes, you guessed it, Lito Sheppard. Otherwise they were targeted on more interceptions (two) than first downs (one).
(Remember when Sheppard went to the Pro Bowl? Man, he has fallen REALLY far.)
When the Eagles defense tries to get to Kurt Warner, that's a battle of strength against strength. Philadelphia's defense ranked third in Adjusted Sack Rate, while Arizona's offense was seventh, and as we've noted in earlier weeks, offensive ASR was the only place where Arizona improved over the second half of the season. During the Thanksgiving blowout, Philadelphia didn't actually have a sack on Warner, one of only three games where the Eagles defense went without a sack.
Even if Philadelphia's pass rush can't take down Kurt Warner, though, it will annoy the hell out of him. Philadelphia led the league in usage of zone blitzes, the only team to zone blitz more than 10 percent of the time. Arizona's offense had a problem with zone blitzes, gaining two fewer yards per play when the defense zone-blitzed. (Note that the phrase "zone blitz" does not necessarily imply complete zone coverage behind the blitz. Philadelphia would be better off going with a "double-cover Larry Fitzgerald and zone everywhere else" blitz.)
With all that blitzing, the Cardinals would be wise to call a few screen passes. It was a play they found surprising success with all season. 57 percent of Arizona's running back screens met our definition of success (based on down and distance), better than any offense except New Orleans. Philadelphia's defense, meanwhile, was slightly below average against running back screens.
Arizona's offense will look to dictate play on first down, where they ranked fifth in the NFL (and first before their late-season swoon). During the regular season, Arizona got their yardage on first down by throwing the ball. The Cardinals passed on 58 percent of first downs; only Denver and New Orleans passed more frequently on first down. That's why it has been so weird to watch the Cardinals run on two-thirds of their first downs over the past two weeks. There has been a lot of talk about Arizona getting the running game going over the last couple weeks, but that might have less to do with the Cardinals and more to do with their opponents. Atlanta ranked 25th in run defense DVOA this year. Carolina was 24th. Philadelphia, on the other hand, ranked third against the run overall and second against the run on first down. There's a pretty good chance that Edgerrin James is going to get un-rejuvenated on Sunday (or would that be re-unjuvenated?). Honestly, the Arizona running game wasn't even as good as you might think during the last two weeks. Both James and Tim Hightower combined for 25 rushing DYAR against Atlanta, but after factoring in the quality of the Carolina run defense, they earned -2 rushing DYAR against the Panthers.
One other thing to watch when the Cardinals have the ball: the officiating. Arizona ranked seventh in the NFL in penalties (including declined and offsetting), and earned 2.3 flags per game more than the Eagles, who ranked 29th. The difference is almost entirely in offensive penalties. Perhaps the most remarkable number: Arizona led the league with 10 Delay of Game penalties, all on offense (as opposed to special teams). No other team had more than seven Delay of Game flags on offense.
|Full Season||Without ARI 13-16|
|PHI OFF||ARI DEF||PHI OFF||ARI DEF|
|DVOA||9.3% (12)||9.3% (21)||5.4% (17)||-1.8% (9)|
|WEI DVOA||4.9% (17)||2.3% (12)||1.0% (21)||-8.8% (6)|
|PASS||12.2% (13)||19.7% (23)||9.5% (15)||8.1% (16)|
|RUSH||5.4% (11)||-1.7% (15)||-0.3% (18)||-13.4% (6)|
|RED ZONE||1.8% (19)||9.8% (21)||-10.4% (26)||3.9% (19)|
Discussions of the Philadelphia offense generally start with Donovan McNabb, but given the events of Thanksgiving night, it may be better to start by talking about Brian Westbrook. Our imaginary world without Arizona Weeks 13-16 has its biggest effect on the numbers for the Eagles running game and the Cardinals run defense, because Westbrook had his best rushing game of the season against the Cardinals. He carried the ball 22 times for 110 yards and two touchdowns. He was also very consistent -- 19 carries earned at least two yards and one of the other three carries was a touchdown plunge. Overall, the Eagles gained 188 yards on 37 carries (not counting Kevin Kolb's kneeldowns).
Westbrook's knee injury is chronic at this point, something that has to be managed from week-to-week. At some point in mid-December, he had some sort of setback and he hasn't been the same since.
|Brian Westbrook vs. His Own Knees|
A gimpy Westbrook needs a lot of rest, and the best thing the Eagles can do is use more Correll Buckhalter. Because of Westbrook's late-season struggles, Buckhalter actually ended the regular season with a better DVOA and Success Rate -- and significantly better numbers as a receiver. Buckhalter missed the Thanksgiving night game with a knee injury but at this point he's definitely healthier than Westbrook (although it should be noted that Buckhalter hasn't been so good in the playoffs so far, outside of his 27-yard carry in the first quarter of the Minnesota game).
Either way, the best way for Philadelphia to run is up the middle. Sometimes that means regular runs, other times draws, but the Eagles were fifth in Adjusted Line Yards up the middle, while the Cardinals were 29th on defense.
The Eagles were well known early in the season for their troubles running in short-yardage situations, but things improved around midyear. The addition of fullback Kyle Eckel in Week 13 was a big part of that, although the turnaround actually began before Eckel was activated.
|Philadelphia on Third/Fourth Down|
|Run DVOA||Yd/Carry||Success Rate|
Oddly enough, the Eagles' passing DVOA on third down declined after Week 10, but it doesn't seem to be connected to the improvement on the ground. It's mostly related to McNabb's Week 11-12 slump and a couple of late-season receiver fumbles. For the entire season, Philadelphia's offense was sixth in the league when throwing on third and fourth down, and the Arizona defense was 31st against the pass on third and fourth down. (In our pretend world where Arizona didn't play Weeks 13-16, their rank improves to 21st.)
Part of the problem on third down was the unit that has looked so good these last two weeks: the pass rush. The Cardinals sacked Matt Ryan twice on third down in their first playoff game, but back during the regular season they had major problems getting to the quarterback on third down. On first and second down combined, the Cardinals ranked 11th in Adjusted Sack Rate. On third and fourth down, they were 31st, worse than every team except Kansas City.
Looking at the week-to-week graphs, you will notice that Arizona's defensive performance was all over the map this season. McNabb's inconsistency, on the other hand, consists almost entirely of a two-game slump against Cincinnati and Baltimore two months ago. If Arizona really isn't the team that they seemed to be in December, isn't it also true that McNabb is not the quarterback that he was in Weeks 11 and 12? In that case, we're talking about one of the five best quarterbacks in the league this year, facing a league-average pass defense.
Remember how I said that the Cardinals fielded the same lineup all year, even during their late-season collapse? That's not entirely true, at least when it comes to the game against the Eagles. Just as Asante Samuel's injury absence affected the Philadelphia defense on Thanksgiving night, so too did Roderick Hood's injury absence affect the Arizona defense. Mike Sando pointed out at the time that Hood's absence may have been the reason the Cardinals switched from their usual Cover-3 defense to playing more Cover-2 and Cover-4 against the Eagles. Clearly, the Cover-2 and Cover-4 did not work very well. It also forced Adrian Wilson off the line of scrimmage, which probably contributed to Brian Westbrook's big day on the ground.
Even with Hood back, McNabb will find weaknesses to exploit in the Arizona secondary. Hood is the best corner on the Cardinals but can be burned deep. Dominique Rodgers-Cromartie has tons of natural talent but makes rookie mistakes. Eric Green is, well, Eric Green. Just like Arizona, Philadelphia used "other wide receivers" on more than 20 percent of passes. Unlike the Philadelphia defense, the Arizona defense is not good against these receivers, ranking 27th in DVOA. In the first game between these teams, Jason Avant and Hank Baskett combined to catch nine of 11 passes, moving the chains five times and scoring a touchdown.
The defense against "other wide receivers" is just one of the many statistical weaknesses of the Arizona pass defense. If we re-run the numbers without Weeks 13-16, the weeks Arizona may not have been trying their hardest, do these stats improve significantly? Not really.
So if the Arizona pass defense had all these weaknesses during the regular season, what the heck changed in the playoffs? There seem to be two clear answers. First, significant improvement on third down, where Matt Ryan and Jake Delhomme completed just 45 percent of passes. Second, oodles and oodles of turnovers, especially by Delhomme. Repeating that is going to be a bit of a problem. From 1995-2007, there were 27 different playoff games where a team caused five or more turnovers on defense (including fumbles recovered by the offense). The next week, these teams averaged just two turnovers. The 2000 Baltimore Ravens were the only team to manage five turnovers in two straight weeks. Donovan McNabb is simply not going to throw five interceptions to the Arizona Cardinals.
|DVOA||1.6% (13)||-3.1% (28)|
|PHI kickoff||3.5 (13)||-1.8 (18)|
|ARI kickoff||4.3 (10)||-7.7 (28)|
|PHI punts||3.4 (15)||-6.5 (28)|
|ARI punts||0.1 (15)||-6.6 (26)|
|FG/XP||-1.8 (21)||4.2 (11)|
Philadelphia clearly has the advantage over Arizona in special teams. It really doesn't have to do with the Eagles, who were a little above average in most areas of special teams. It has to do with the Arizona coverage units. Based on gross value (i.e. assuming average returns), kicker Neil Rackers and punter Ben Graham were both above-average. However, the Cardinals gave up more value on kickoff returns than any team except Kansas City, and more value on punt returns than any teams except Minnesota and Washington. Combined, the Arizona coverage teams gave up an estimated 22 points worth of field position compared to the NFL average. That opens things up for Quintin Demps or DeSean Jackson to make a big play.
The Philadelphia coverage units were fairly average over the course of the season but the numbers show a huge improvement in kickoff coverage after the Eagles picked up ex-Green Bay linebacker Tracy White, who's known for his special teams play. Over the first six weeks, opposing kickoff returns were worth 4.6 points worth of field position over average. Since Week 7, opposing kickoff returns have been worth -3.4 points worth of field position compared to average. The Eagles allowed six kickoff returns over 30 yards in the first six weeks, then didn't allow another kickoff return over 30 yards until the final game against Dallas. (White had no effect on the statistics for punt coverage.)
The other issue that might come into play is David Akers' struggles on long field goals. Over the last three regular seasons, David Akers has been slightly above-average on field goals of less than 45 yards. He is just 6-for-17 on field goal attempts of 45+ yards over the same time period.
There's very little chance that the Cardinals offense will overwhelm the Eagles defense or vice versa. Both units are fairly consistent, and both units should play well. That means this game will mostly be decided when the Eagles have the ball. The Westbrook injury makes their offense even more one-dimensional than usual. The Cardinals have home-field advantage and probably emotion on their side. However, nearly all the on-field matchups favor the Eagles passing game over the Cardinals pass defense -- even if we assume that Arizona's poor play from Week 13 to Week 16 "doesn't really count."
Lots of things can happen in a football game. A couple of bounces of the ball can throw the game one way or the other. Donovan McNabb could revisit his Week 11-12 slump and go all Delhomme on us, especially if a gimpy Westbrook means he's always facing third-and-long. Larry Fitzgerald could go beyond even his usual outstanding level of play and win the game on his own -- especially if Anquan Boldin is on the field to draw some of the secondary's attention. All these things are possible, but while we often say that probability is not a guarantee, but it is also true that possibility is not probability. Philadelphia is the better team and more likely to advance to Super Bowl XLIII.
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.
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). These numbers are all regular season only, except for WEIGHTED DVOA which includes the playoffs.
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 also gets two charts showing their performance this year, game-by-game, according to offensive and defensive DVOA. In addition to a line showing each game, another line shows the team's trend for the season, using a third-power polynomial trendline. That's fancy talk for "the curve shifts direction once or twice."
160 comments, Last at 19 Jan 2009, 11:54am by Spielman