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Chargers Stat of the Day: Defensive Ratings

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Attention all nerds.  Do you head straight to Football Outsiders when you're looking for better-than-average stats?  Well, I found another website that you're going to want to bookmark.  (Editor's Note: This is not a paid advertisement.  I've never even talked with the guys from this website.  So if this sounds like a sales-pitch, it's not.)

ProFootballFocus.com is a website that football stat-geeks have been dying for without knowing it.  Just about any question you have about the team can be answered within their stats.  Want to know who has played the most defensive plays for the Bolts?  Eric Weddle, with 544.  How about which player has the most QB Pressures?  It's a tie between Luis Castillo and Shaun Phillips (both have 10).  Wondering who the best MLB on the Chargers is?  You'll be surprised.

Let's delve into some of PFF's defensive stats and player ratings...

I was taught a long time ago to never argue with someone who was smarter than me.  I almost never abide by this rule, but today I'll make an exception.  These guys have done such a great job at collecting stats, that I'm going to assume they do just as good of a job comparing them.

In terms of defense, it appears they look at all of the stats (sacks, QB hits, QB pressures, tackles, penalties, missed tackles, stops) and compare them relative to the number of plays the player had played.  So a played like Brandon Siler, who has 10 stops on 104 plays, would be looked at as a more efficient player when he's on the field than Stephen Cooper (22 stops in 454 plays). 

Each player is rated based upon their work rushing the passer, stopping the run and in pass coverage.  Also factored in are things like Penalties being called against that player (surprisingly, leading the Chargers D in penalties is a tie between Shawne Merriman, Shaun Phillips and Larry English) and Missed Tackles. 

The missed tackles stat also needs to be looked at proportionally against actual tackles.  For instance, Stephen Cooper leads the team with 10 missed tackles to go with his 48 tackles on the season.  However, that's probably not as bad as Antonio Cromartie's 6 missed tackles with only 15 tackles to his name.

So, follow me down the rabbit hole as we look at PFF's ratings of Chargers defensive players by position group.  The number next to each player is their PFF Rating, which is roughly explained here.  In a nutshell, zero is average across the league and any number above that is above average.  Any number below is obviously below average.  Also, for the sake of this not being too confusing, I'm leaving out any player who has been on the field for less than 75 snaps.

Defensive Line

  1. Travis Johnson -1.5
  2. Ian Scott -3.0
  3. Alfonso Boone -3.1
  4. Ogemdi Nwagbuo -3.1
  5. Jacques Cesaire -9.5
  6. Luis Castillo -10.3

How about that trade for Johnson?  The Castillo number is a bit jarring, but appears to be accurate.  Although he's near the top on the team in terms of defensive stops and QB pressures, apparently relative to the number of plays he's played it's just not as impressive as it has seemed.  Also, according to their individual rankings he's fairly average at rushing the passer and well below average at stopping the run.  For those looking for a comparison, Castillo's 2008 was ranked at 0.8 (or just a little above average) and Jamal Williams' 2008 was ranked at 27.4.  27.4!  In 2007, Castillo was well above average at 7.7 when he was on the field.

 

Linebackers

  1. Brandon Siler 5.8
  2. Shaun Phillips 2.7
  3. Kevin Burnett 2.6
  4. Stephen Cooper -2.4
  5. Tim Dobbins -2.7
  6. Shawne Merriman -3.3
  7. Larry English -12.2

I told you this stuff was interesting.  As mentioned above, Cooper is killed by his missed tackles and by being below-average (-1.5) in pass coverage.  Siler is actually the only LB that ranks as above average against the run and in pass coverage this year.  Phillips would probably be #1 if it weren't for the 4 penalties he's picked up this season.  This group is greatly improved from 2008, when no LB ranked as average or above average (Wilhelm was -16.9 if you were wondering).

 

Cornerbacks

  1. Antoine Cason 1.4
  2. Steve Gregory -1.0
  3. Quentin Jammer -3.8
  4. Antonio Cromartie -5.6

Jammer is actually playing better than he did in 2008, when his season ranking was -5.9.  The stats seem a little off for cornerbacks in terms of what's "average", but at least they appear to be consistent.  Cromartie's 2008 rating?  -27.4.  He was the anti-Jamal Williams.

 

Safties

  1. Eric Weddle 3.7
  2. Paul Oliver 0.5
  3. Clinton Hart -1.8
  4. Kevin Ellison -2.7

Before you start screaming about Hart being rated ahead of Ellison, listen up.  Here's what I gather as the explanation by looking at the stats they're presenting.  Both players are equal against the run (0.5), and the rookie actually better in pass coverage (-2.3 to -3.7), but the main two factors that catapult Hart above Ellison is penalties (zero for Hart, 2 for Ellison) and pass rushing (1.4 for Hart, 0.1 for Ellison).  I can't entirely disagree with that, and considering these guys are charting the plays and I'm not....I'm going to believe them. 

Still, it was the right move to get rid of Hart.  Ellison is an improving player and Clinton was a declining one.  Also, it has opened up plenty of playing time for Paul Oliver (who is obviously playing well).

 

So what do you guys think?  Interesting stuff, right?  Obviously, like all stats, these are not perfect.  From what I can tell, these ratings do not factor in the level of competition being faced (which explains why Gregory would be higher than Jammer and Cromartie) nor do they factor in double-teams (which explains why Luis Castillo is down this year and why Shaun Phillips had such a poor rating in 2008).  Still, in terms of judging who is making the most impact with their time on the field....it's intriguing.

Stats and rankings taken from ProFootballFocus.com do not include information from the Week 10 match-up against the Philadelphia Eagles.