by Aaron Schatz

So, it's time to start going through all the various numbers we have for 2011. I want to apologize for taking so long to do some of this. The game charting project ended up running a bit long this year trying to catch up with missed game. Other features haven't been updated yet because we had a bad run of interns taking forever to do projects or straight-out disappearing on us. That's one reason, for example, why the player pages have not yet been updated with 2011 data and 2009-2011 similarity scores. Hopefully we'll be able to make those updates soon. (I also was holding out until I finished with a new version of DVOA that normalized every season to 0% and looked at questions about the "red zone bonus," but it doesn't look like that will be ready for another few weeks.)

Anyway, the game charting has been complete for a few weeks, and now we've had a chance to do some cleaning on it where two charters disagree, and overall I'm ready to toss out some numbers. These are updated versions of the numbers I ran here in December. As usual, the typical caveats about the game charting apply: This is imperfect data based on the game charting project, which means it comes off limited television camera angles, and it is charted by a group of volunteers plus a handful of FO staff members. Sometimes a cornerback will benefit because he happens to be in coverage when a quarterback throws a bad pass, even if he wasn't covering close. Sometimes a cornerback will benefit from a better pass rush, because it's easier to cover when you don't need to cover for six seconds. As we always say, these stats should not be seen as absolute statements on player value. They're just part of the story.

These tables rank all cornerbacks with at least 40 charted passes. I removed all safeties except for Antrel Rolle, who is often playing as a cornerback when the Giants are in nickel (which they are an awful lot of the time). As we do with the cornerback charting stats in the book and on the player pages, I've removed passes marked as Hail Mary, Hit in Motion, Tipped at Line, or Thrown Away. I've also removed wide receiver screens, which aren't really a good way to measure cornerback coverage because a cornerback in man coverage is going to (or at least, is supposed to) immediately get blocked out of the play by another wide receiver. Right now I'm only looking at primary defenders, so this is not adjusted to account for double coverage, or plays where the charter marks a hole in zone but lists an appropriate zone defender in the second DEFENDER column. There are no opponent adjustments yet. However, pass interference is included. No other defensive penalties are included. With defensive pass interference, the defender flagged is almost always the player who was in coverage on the intended receiver; with illegal contact or defensive holding, the flag often comes far away from where an actual pass may be thrown.

We'll start with the cornerbacks who allowed the fewest yards per pass according to our game charting.

Cortland Finnegan had an excellent year and demonstrates the kind of year-to-year variability we've found to be a problem with these cornerback charting stats. He was also near the top of the league in 2009, but in 2010 he ranked 65th in Success Rate and 76th in yards per pass. Which cornerback are the Rams getting next year? Perhaps we need to look at whether cornerback charting stats have more consistency if we look at them two or even three years at a time. The flipside to Finnegan's inconsistency would be Asante Samuel's consistency. Samuel ranked first in both yards per pass and Success Rate in 2010, then third in both for 2011. Yes, this is the guy the Eagles are trying to trade because they want to be able to move Dominique Rodgers-Cromartie outside and play more man coverage. Samuel is still really good and would be a huge addition to any team that plays primarily zone coverage.

In between Finnegan and Samuel, that's 2009 Houston sixth-round pick Brice McCain taking advantage of the Texans' newly vigorous pass rush to blanket opposing receivers. Culliver, Verner, and Allen also fall into the nickelback category. And we talked about rookie Richard Sherman's phenomenal year a bit when we did the midseason update.

Notice someone missing? When I ran the midseason update on game charting for cornerbacks, Darrelle Revis ranked first in the league in both yards per pass and Success Rate. Now that we have stats for the entire season, he ranks 16th in both stats. Now, that's still nicely above average, and given the variability in cornerback stats I noted just above, the drop shouldn't be seen as incontrovertible evidence that Darrelle Revis is no longer the best cornerback in the National Football League. I would still take him ahead of everyone else (unless I was absolutely wedded to playing a zone scheme; then I would probably take Samuel).

Why did Revis fall so much in this final tally of cornerback charting stats? First of all, we were missing a lot of Jets charting when I ran that first batch of numbers in December, so Revis' numbers were based on a smaller sample size than those of other starting cornerbacks. The other reason for Revis' drop is that Revis himself apparently struggled a bit during the second half of the season. Check out his charting stats split into before and after the Jets' Week 8 bye:

Player Charted

Targets Yd/Pass Success

Rate Avg. Pass

Distance YAC Weeks 1-7 31 3.9 68% 16.5 1.7 Weeks 9-17 50 7.8 56% 11.3 3.8

This could be noise. It could be evidence that the knee injury that limited Revis in practice during the final two months of the season was a bigger deal than anyone realized. It could also be evidence that Revis has lost his place as the best cornerback in the league. Could be. I don't think it is.

Fortunately for the Jets, this falloff from Revis was offset by surprising improvement from Antonio Cromartie:

Player Charted

Targets Yd/Pass Success

Rate Avg. Pass

Distance YAC Weeks 1-7 36 7.4 50% 14.1 1.8 Weeks 9-17 38 6.2 71% 17.8 2.7

Next, we'll look at the top cornerbacks in Success Rate. Success Rate, to remind everyone, is the percentage of passes that don't manage to get at least 45 percent of needed yards on first down, 60 percent of needed yards on second down, or 100 percent of needed yards on third down.

This table has some of the same names, and some surprising ones. Chris Gamble and Richard Marshall were both horrible in 2010, and both were a lot better in 2011 -- one with a new defensive coordinator, and the other with a new team.



This next table is more for conversation than for any kind of evidence of which players were or were not very good this year.

One more tidbit for today. I talked above about Asante Samuel's great year. What about the other Philadelphia cornerbacks? Well, it turns out we don't actually have the minimum 40 charted targets for any of the other Eagles cornerbacks. So I'll just present them all in one table so Eagles fans can have fun debating whether the team is making the right move by trying to deal Samuel. There's also a strong debate to be had about whether the Eagles were just using Nnamdi Asomugha wrong, or whether he's really not as good as we all thought.

Philadelpia Eagles Cornerbacks 2011 Player Charted

Targets Yd/Pass Success

Rate Avg. Pass

Distance YAC Asante Samuel 61 4.4 67% 14.7 2.0 Joselio Hanson 39 7.6 49% 10.6 3.3 Nnamdi Asomugha 36 9.0 56% 15.8 2.5 Dominique Rodgers-Cromartie 33 6.9 61% 13.6 5.8

Next week, I'll flip the script and run "10 worst" tables for cornerback charting stats.