By Aaron Schatz
Special to Page 2

Note: Go to the bottom of the table for a more complete explanation of how Aaron's QB rating system works.

One of the most important parts of these ratings is the adjustment for opponent. Passing for 300 yards on the Saints is not the same as passing for 300 yards on the Steelers. So this week, I thought I would switch things around and show the rankings of the best and worst defenses in terms of PAR given up to opposing quarterbacks.

This is especially noteworthy this week because the two biggest quarterback performances were significantly affected by the quality of the opposing defense. If we don't adjust for opponent, Donovan McNabb's 464 and 5 TDs against Green Bay was easily the best performance, followed by Carson Palmer, Kerry Collins and Peyton Manning. But Green Bay has given up more big passing games than any other team, and the Ravens have been the best defense in football. When you adjust for that, Palmer's game actually scores as more valuable than McNabb's game, with Manning third and Collins a bit farther down because a big offensive performance came against Kansas City.

Carson Palmer's big day also shows that, just like the quarterbacks they face, great defenses can have bad days and bad defenses can have surprisingly good days. I'm guessing that fantasy football players everywhere did a double take watching the ticker at the bottom of the screen as Buffalo and Miami racked up the points and St. Louis and San Francisco had a defensive struggle. It was like "Freaky Friday," only without Lindsay Lohan.

Anyway, here's a list of this season's 10 best and worst defenses, ranked by how many Points Above Replacement they've given up to opposing quarterbacks. The difference here is that instead of adjusting for the defense, the numbers are adjusted for the opposing offenses. After all, you don't want to penalize those poor AFC South teams that have to face Peyton Manning twice.

Top pass defenses    Worst pass defenses
Team     PAR         Team      PAR
BAL    -14.7         GB        86.9
PIT    -11.5         NO        86.3
NE      -6.5         STL       80.6
TB      -4.7         SF        80.0
CHI     -3.6         MIN       77.5
DEN      3.2         OAK       69.3
TEN      5.4         DAL       63.9
PHI     11.2         KC        55.3
WAS     11.8         IND       41.7
BUF     13.9         JAC       40.7

*Not counting Monday Night Football this week.

  • Get overall season rankings at footballoutsiders.com.

    SNAP JUDGMENT'S QB RANKINGS FOR WEEK 13
    Quarterback Skinny DPAR
    1. Carson Palmer
    29/36, 382 yards
    3 TDs, 1 INT
    At the age of 13 weeks, the little boy became a man before our eyes. I think I'll send him a bar mitzvah card. 17.6
    2. Donovan McNabb
    32/43, 464 yards
    5 TDs, 0 INTs
    As great as this was, Manning's Week 3 against the Packers was even better, 17.2 DPAR after adjusting for the poor Green Bay secondary. 14.1
    3. Peyton Manning
    25/33, 425 yards
    3 TDs, 2 INTs
    Hopefully Edge's two rushing TDs end that "selfish Manning" nonsense. 13.7
    4. Patrick Ramsey
    19/22, 174 yards
    3 TDs, 0 INTs
    The "Brady Anderson hits 50 homers" game of the week. 12.8
    5. Drew Bledsoe
    19/30, 277 yards
    4 TDs, 0 INTs
    "Euhus" is apparently pronounced "HEW-is" but I'm still skeptical. 12.6
    6. Byron Leftwich
    16/27, 268 yards
    1 TD, 0 INTs
    Great game throwing to Bizarro Troy Edwards, 90 yards and a TD after averaging 33 yards a game with no TDs this year. 11.8
    7. Ben Roethlisberger
    14/17, 221 yards
    2 TDs, 0 INTs
    One of these weeks, Pittsburgh is going to win a game with Big Ben throwing fewer than 10 passes. 10.9
    8. Kerry Collins
    27/41, 343 yards
    3 TDs, 0 INTs
    This had to be one of the more exciting "playing out the string" games of all time. 9.2
    9. Trent Green
    23/35, 340 yards
    3 TDs, 1 INT
    One reason KC underachieves? Only 5-for-16 in goal-to-go situations this season, with two interceptions and two sacks. 8.2
    10. Jake Delhomme
    22/29, 294 yards
    1 TD, 0 INT
    Disappointing day for senior Daily Show football correspondent Keary Colbert, with only one catch. Jon? 6.1
    11. Luke McCown
    20/34, 277 yards
    2 TDs, 2 INTs
    Better than he looked, since he was playing against a top defense and always stuck in 3rd-and-long because the Browns have no running game. Even converted two fourth downs. 4.5
    12. Chad Pennington
    20/27, 155 yards
    2 TDs, 1 INT
    Jets fans dry-eyed over end of Quincy Carter era. 4.4
    13. Kyle Boller
    19/33, 172 yards
    0 TDs, 1 INT
    Can you really see him going into Pittsburgh or Foxboro and winning in January? 3.7
    14. Eli Manning
    12/25, 113 yards
    0 TDs, 0 INTs
    Sure, no interceptions, but also only one pass for more than 11 yards. 1.7
    15. Tom Brady
    11/20, 157 yards
    1 TD, 1 INT
    69 rush
    Browns were really getting a pass rush on him, and he was missing guys all day. Rest of the Patriots picked up the slack. 0.8
    16. Aaron Brooks
    20/40, 251 yards
    3 TDs, 2 INTs
    211 passes this season when losing by more than a TD, 55 more than anyone else. 0.4
    17. Joey Harrington
    15/27, 196 yards
    1 TD, 1 INT
    The Cardinals said, "We'll stop the pass and dare the run to beat us." And so it was. 0.0
    18. Daunte Culpepper
    23/33, 279 yards
    2 TDs, 3 INTs
    Beware the power of Brancato: dome and warm-weather teams fold when playing in a cold-weather city in December. 0.0
    19. Chad Hutchinson
    18/30, 213 yards
    3 TDs, 0 INTs
    Bears fans, don't get giddy just yet -- eight QBs have thrown for more yards on the Vikings, and Hutchinson got sacked five times. -0.1
    20. Chris Chandler
    18/27, 216 yards
    1 TD, 1 INT
    Chandler and Marshall Faulk must have quite a battle for the Metamucil and Efferdent in the St. Louis trainer's room. -0.4
    21. Brian Griese
    13/21, 131 yards
    1 TD, 1 INT
    Just happy to not have Tim Brown as his No. 1 receiver anymore. -2-2
    22. A.J. Feeley
    25/51, 303 yards
    3 TDs, 5 INTs
    Three TDs in the first quarter to put Miami ahead, three interceptions in the fourth quarter to give Buffalo the game. -3.3
    23. David Carr
    12/25, 157 yards
    0 TDs, 2 INTs
    Finally, the answer to "If man is five, and the devil is six, and God is seven, who is eight?" -3.6
    24. Drew Brees
    14/27, 106 yards
    0 TDs, 1 INT
    He was the old Drew Brees, but that was still better than the current Jake Plummer. -6.0
    25. Tim Rattay
    10/21, 121 yards
    0 TDs, 1 INT
    That's four straight games below replacement level. What's happened to this guy? -7.6
    26. Michael Vick
    13/27, 115 yards
    0 TDs, 2 INTs
    Vick was worth 3.7 DPAR rushing (81 yards), so this was actually the second-worst passing performance of the day. -7.8
    27. Billy Volek
    21/35, 269 yards
    3 TDs, 2 INTs
    I have a macro on my laptop so when I press Ctrl-V, it types, "Volek, in for the injured McNair." -8.2
    28. Brett Favre
    14/28, 131 yards
    0 TDs, 2 INTs
    Career 0-4 record in Philadelphia. Allergic to cheesesteaks? -8.4
    29. Jake Plummer
    16/40, 228 yards
    0 TDs, 4 INTs
    A performance like this in a must-win game has to earn Plummer the biggest goat horns of the year, although I'm never quite sure how much blame a QB deserves when a ball is tipped by a receiver and then intercepted. -11.2
    30. John Navarre
    18/40, 168 yards
    1 TD, 4 INTs
    Hey, it's another low-round draft pick QB from Michigan! What could go wrong? -14.0

    How DPAR (Defense-adjusted Points Above Replacement) works

    The success of each play is judged based on yardage gained towards both a touchdown and a first down. Then each play gets compared to the NFL average on similar plays, based on down, distance, and other variables. Quarterbacks are judged not based on how many yards they get, but on how important those yards are in the context of the game.

    Ratings are also adjusted for the quality of the opposing defense. The quarterback's performance is then translated into an approximate number of actual points that such success (or failure) is worth when compared to a "replacement level" quarterback (defined as any quarterback named "Billy Joe").

    When all offensive, defensive, and special teams plays are added together for one team, the result comes very close to the actual difference between points scored and allowed.

    Among the advantages of this system:

    1. Gives value for first downs, which are not really included in any other QB rating system but are hugely important.

    2. Does not punish quarterbacks who are always in bad field position because of a poor defense, nor does it punish quarterbacks who are always stuck in third-and-long because of a poor running game.

    3. With enough data to begin including defensive adjustment, quarterbacks receive bonuses when they play well against good defenses, and they don't get rated as world-beaters when they shred the 49ers

    4. Includes both passing and rushing plays, which obviously helps a QB like Michael Vick.

    5. DPAR punishes quarterbacks for turnovers but also for fumbles that his own team recovers. Different kind of fumbles have different penalties depending on how often defense recovers for a turnover. Sacks are punished as well.

    6. 5-yard scramble on 3rd-and-10? Worthless!

    7. Actual points! Easy to understand!

    An even longer explanation of these numbers can be found here.

    Aaron Schatz is editor-in-chief of FootballOutsiders.com.




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