Writers of Pro Football Prospectus 2008

17 Nov 2006

Early game charting data on yards per pass vs. defensive backs

This is the second year of the Football Outsiders game charting project, where we have an army of volunteers charting new stats during games that aren't kept in the standard play-by-play. We can't use these stats much during the season, because the game charting lags behind the actual games by at least a week, usually more. But now that we have eight weeks mostly charted, I thought it would be fun to look at some of the data to see what we can find.

We'll start with yards per pass allowed by defensive backs. This is one of two stats we used to track DBs in Pro Football Prospectus 2006. The other one was Stop Rate, or the percentage of passes against a defensive back that were successful. Both stats are useful -- for example, in Indianapolis, Nick Harper has a great yards per pass allowed and a terrible Stop Rate, while Jason David has a good Stop Rate and awful yards per pass allowed. Harper gives up more first downs, but when David gets beat, he gets beat BADLY.

Keep in mind that this data is really preliminary. Really, really preliminary. A number of games from Weeks 4-8 still aren't finished, and this doesn't include Weeks 9-10 at all. These numbers include passes that are incomplete for a lot of reasons that have nothing to do with the defensive backs, although we've removed quarterbacks hit while throwing and passes tipped/batted down at the line. Also remember that there isn't much difference between being ranked first and being ranked ninth -- the difference is between being ranked in the top ten vs. the bottom half of the league, or something like that.

That being said, let's look at yards per pass allowed, according to our charters. Here are the top dozen defensive backs so far with at least 10 passes charted. The numbers represent charted passes and net yards per pass.

1. 43-T.Polamalu PIT 12 1.8
2. 38-T.Poole OAK 14 2.1
3. 42-D.Sharper MIN 12 3.0
4. 25-K.Rhodes NYJ 15 3.9
5. 20-B.Dawkins PHI 18 3.9
6. 22-F.Thomas NO 43 4.0
7. 25-A.Cromartie SD 17 4.2
8. 28-L.Bodden CLE 23 4.3
9. 40-M.Williams CIN 12 4.3
10. 21-B.Pool CLE 10 4.4
11. 24-M.Huff OAK 10 4.4

That's certainly a mix of surprises and non-surprises. Let's start with the non-surprises., We've written many times that Leigh Bodden is one of the top corners in the league, and the most ignored by the press. Tory Polamalu is good and rarely plays deep, a good combination for this stat. Darren Sharper was near the top for safeties last year. Dawkins is a Pro Bowler. Below this list but still in the top 20 are Champ Bailey, Adrian Wilson, Deltha O'Neal, and Asante Samuel.

Now the surprises. Tyrone Poole???? Yes, really. We made fun of Oakland for picking up the veteran cornerbacks who sucked in New England last year, but actually only Duane Starks sucked last year -- Poole was just injured. I doubt he's really going to be this good all year, but this is not an issue of Poole only playing short or something -- three of the incompletes are passes of 30 yards or more. And he's allowing less than three yards after catch on the few completes he has allowed, none of which went more than five yards in the air. Seriously.

Let's see who else -- New Orleans should be happy to get Fred Thomas back from his hamstring injury. Thomas also did far better than Mike McKenzie in this stat for 2005. Yes, Jets safety Kerry Rhodes did well in this stat last year too, believe it or not. Antonio Cromartie really is having a shockingly good rookie year, and he's not the only rookie that we were completely wrong about -- Donte Whitner is in the top 20 too. Mea culpa. Michael Huff is also playing well, and Brodney Pool is another part of the emerging Cleveland defense.

OK, now the flip side.

1. 27-R.Whitaker MIN 11 15.4
2. 21-O.Atogwe STL 10 14.6
3. 22-S.Rolle BAL 29 14.2
4. 20-M.Adams SF 16 14.1
5. 23-J.Phillips TB 14 13.1
6. 22-M.Manuel GB 13 12.8
7. 32-M.Lewis PHI 14 12.6
8. 20-E.Reed BAL 11 12.4
9. 26-D.Landry BAL 12 12.2
10. 26-E.Wilson NE 16 12.1

What the hell are all these Ravens doing here? Aren't they the best defense in football so far? Remember -- this doesn't include the game against Tennessee, and every Baltimore game from Week 1-8 is fully charted except for portions of Week 4. I seriously have no idea what's up here. Reed was very good in this stat last year. Samari Rolle was much better than Chris McAlister last year, but this year, McAlister is allowing just 6.2 yards per pass. We have 22 of 29 passes with Rolle in coverage listed as complete, including a 72-yard touchdown to Steve Smith, a 58-yard touchdown to Braylon Edwards, a 47-yard touchdown to Marques Colston. One of the two interceptions was actually by Bart Scott, and three of the five incompletes are listed as drops!

Is Rolle just losing it? It seems like it should be a fluke, but the cornerback numbers are a lot easier to trust than the safety numbers, because there are so many more passes charted with cornerbacks as the defenders in coverage. I think everyone else on that list is a safety. Other cornerbacks who do poorly in this stat are Terry Cousin, Gary Baxter (surprise!), Brian Williams (also surprise!), Ahmad Carroll (completely not a surprise!) and Tory James. At least quarterbacks taking on Cincinnati know who they should be throwing on.

By the way, Dallas safety Pat Watkins barely misses the list because he only has nine charted passes, but he allowed a mind-blowingly awful 21.6 yards per pass. Has he considered becoming a linebacker, perhaps?

Posted by: Aaron Schatz on 17 Nov 2006