Writers of Pro Football Prospectus 2008

17 Jan 2007

NFC Championship: Who Covers Who

One of the big stories this weekend is whether the New Orleans Saints and New England Patriots can hide their weaknesses at cornerback. On the Saints, one corner (Fred Thomas) has given up big plays far more often than the other two. On the Patriots, one corner (Asante Samuel) is much better this season than the other two.

Let's go through data from the Football Outsiders game charting project to see what we can learn about who each cornerback might end up covering during the game. We've assigned each offense with #1 WR and #2 WR for each week, with other WR into a third category and TE as a fourth category.

Standard caveats apply: Charting off of television camera angles is bound to have mistakes. This information is incomplete, because we aren't finished with every game yet. Designations of "#1 WR" and "#2 WR" are somewhat arbitrary, and it would be better to mark "flanker" and "split end" except that we have no record of which players were on which side on every play. "Other WR" doesn't necessarily designate slot receiver, since sometimes the top guy will move to the slot in a three-wide.

Anyway, none of this means we can't learn something, so let's see what we find when we look at which defenders cover which receivers the most often for each team.

Chicago Bears

vs. #1 WR
• 33-C.Tillman 48%
• 31-N.Vasher 18%
• 55-L.Briggs 6%
• 24-R.Manning 5%
• Uncovered/Hole in Zone 5%
• Other 17%

vs. #2 WR

• 33-C.Tillman 24%
• 31-N.Vasher 19%
• 24-R.Manning 15%
• 55-L.Briggs 7%
• Uncovered/Hole in Zone 7%
• 54-B.Urlacher 5%
• 38-D.Manning 5%
• Other 19%

What you see here are three things.

In the Bears' Tampa-2 defense, Charles Tillman and Nathan Vasher aren't usually assigned to specific receivers. But it doesn't matter whether the quarterback is throwing to one starter or the other -- he's going after Tillman more often.
Because of the Tampa-2, the Bears have a higher than normal percentage of passes listed as Uncovered or Hole in Zone.

It's not man coverage specifically, but Lance Briggs probably ends up defending starting wide receivers more than any linebacker in the league.

vs. Other WR

• 24-R.Manning 29%
• 33-C.Tillman 14%
• 31-N.Vasher 14%
• 55-L.Briggs 13%
• Uncovered/Hole 10%
• Other 20%

This responsibility is less specific on some teams (as you'll see when I do the Patriots tomorrow) but on the Bears, that third corner is most often on that third guy. And there's Briggs again.

vs. TE

• Uncovered/Hole in Zone 16%
• 55-L.Briggs 15%
• 54-B.Urlacher 13%
• 46-C.Harris 12%
• 92-H.Hillenmeyer 10%
• 33-C.Tillman 6%
• 31-N.Vasher 6%
• 35-To.Johnson 6%
• Other 17%

The high Uncovered/Hole in Zone number for covering tight ends is very indicative of the Tampa-2.

New Orleans Saints

vs. #1 WR

• 22-F.Thomas 35%
• 21-J.Craft 19%
• 34-M.McKenzie 18%
• 29-J.Bullocks 8%
• 23-O.Stoutmire 5%
• Uncovered/Hole in Zone 1%
• Other 14%

Burn, baby, burn. Disco inferno!

vs. #2 WR

• 34-M.McKenzie 26%
• 22-F.Thomas 25%
• 21-J.Craft 15%
• 58-S.Shanle 7%
• 29-J.Bullocks 7%
• Uncovered/Hole in Zone 8%
• 55-S.Fujita 5%
• Other 8%

The question here is: Is Fred Thomas covering the top receiver more often than McKenzie? Or do opposing quarterbacks just throw to the top receiver more often than he's covered by Thomas. Remember, we can't chart a pass with Thomas covering the #1 WR unless the pass is thrown to the #1 WR. Last week, we talked about the difference between Thomas's performance before and after midseason. Now, look at the difference in where opposing quarterbacks threw the ball:

Weeks 1-8: Thomas covered 28% of charted passes to #1 WR, 32% of passes to #2 WR.
Weeks 9-16: Thomas covered 44% of charted passes to #1 WR, 17% of passes to #2 WR.

And remember, Thomas missed a couple of games in the second half of the season due to injury (Weeks 10 and 12) so when he was in the lineup, those percentages were actually higher.

vs. Other WR

• 22-F.Thomas 32%
• 21-J.Craft 20%
• 34-M.McKenzie 18%
• 29-J.Bullocks 8%
• Uncovered/Hole in Zone 4%
• Other 18%

Yep, he's number one here too.

vs. TE

• 41-R.Harper 16%
• 55-S.Fujita 13%
• 21-J.Craft 11%
• Uncovered/Hole in Zone 11%
• 34-M.McKenzie 8%
• 58-S.Shanle 8%
• 23-O.Stoutmire 8%
• 29-J.Bullocks 7%
• 53-M.Simoneau 7%
• 22-F.Thomas 5%
• Other 7%

Among the myriad of incredible facts about the 2006 New Orleans Saints is this: They got a draft steal in strong safety Roman Harper, who was excellent in pass coverage early, yet they continued to play well even though he was lost for the year after five games. Harper was used so often in pass coverage that he comes out as the most common defender assigned to the tight end -- even though he played just one-third of the season.

Summarizing all this: On each of these teams, quarterbacks prefer to go after one cornerback over the others. But on Chicago, the picked-on cornerback was just as good as the other cornerback this year. That's not true in New Orleans. Advantage: Bears.

Then again, this is all dwarfed by the fact that New Orleans has the better quarterback by leaps and bounds. Advantage: Saints.

We'll do the Patriots and Colts tomorrow.

Posted by: Aaron Schatz on 17 Jan 2007