by Aaron Schatz

Last week, we looked at the cornerbacks with the best charting statistics in our game charting project. Today, we'll look at the cornerbacks with the worst stats.

As usual, the typical caveats about the game charting apply: this is imperfect data 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. The cornerback charting stats have been very volatile, bouncing up and down year-by-year for a lot of players, and the best cornerbacks will occasionally rank lower in these stats because quarterbacks only throw in their direction when they make a mistake. As we always say, these stats should not be seen as absolute statements on player value. They're just part of the story.

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. Once again this year, we're bringing you the most accurate numbers by waiting to post cornerback stats until they've been double-checked. These stats have also been analyzed to give half-credit on plays where we list two defenders in double coverage, or where we listed DEFENDER1 as "Hole in Zone" but also list a specific defender as responsible for that zone. We also have both actual numbers and the metrics adjusted for the quality of receivers each cornerback had to cover. (Two metrics, average pass distance faced by each cornerback and yards after catch, are not adjusted for opponent.)

Pass interference is included, although 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.

There are two main stats we track. The first, Yards per Pass, is simply the average yardage gained on every pass where we list this cornerback in coverage. The other stat, Success Rate, tells you how often the cornerback prevents opposing receivers from what we consider a successful gain: 45 percent of needed yards on first down, 60 percent on second down, and 100 percent on third down. Note that nickelbacks will often rank much better in Yards per Pass than in Success Rate, while starting corners who blew a couple of huge plays over the course of the season will rank much better in Success Rate than in Yards per Pass.

There are 87 cornerbacks ranked who qualified with a minimum of either 50 charted passes or eight games started. To give more information about the cornerbacks that saw the field the most, each table also lists the next three cornerbacks who would be ranked if we limited the minimum to only the 36 cornerbacks who started at least 14 games.

We'll start with the cornerbacks who allowed the highest Adjusted Yards per Pass according to our game charting.

Worst Cornerbacks in Adjusted Yards/Pass, 2013 Player Team Charted

Targets Adj

Yd/Pass Rk Adj

Suc Rate Rk Avg. Pass

Distance YAC Rk 31-A.Cromartie NYJ 84 11.8 87 52% 44 16.6 8.8 87 22-A.Samuel ATL 33 11.5 86 31% 87 14.5 2.6 9 27-R.McClain ATL 53 11.3 85 37% 84 9.6 6.7 82 24-W.Blackmon JAC 48 11.3 84 47% 69 15.5 6.8 83 23-C.Houston DET 77 10.8 83 51% 53 15.2 7.2 84 20-C.Cook MIN 43 10.5 82 35% 85 12.0 3.8 39 21-J.Robinson MIN 45 10.2 81 35% 86 10.3 3.3 25 29-S.Wright SD 84 10.0 80 38% 83 14.1 4.7 66 21-J.Jenkins STL 80 9.9 79 45% 77 12.0 6.0 81 22-D.Cox SD 59 9.4 78 46% 76 13.1 3.3 26 31-M.Cooper KC 83 9.3 77 53% 41 13.4 7.8 86 24-B.Flowers KC 88 9.2 76 47% 75 11.9 5.2 73 39-B.Carr DAL 107 8.9 73 49% 62 12.8 4.9 70 26-J.Wilson WAS 64 8.9 72 49% 63 11.0 4.3 53 24-I.Taylor PIT 109 8.9 71 43% 80 12.7 4.1 50

We often write about how our cornerback charting stats are extremely inconsistent from year to year, but what's surprising about the two cornerbacks who gave up the most yards per pass in 2013 is how consistently good they had been until 2013. Antonio Cromartie had ranked in the top 20 for Adjusted Success Rate each of his three previous years in New York (2010-2012), and in the top 26 for Adjusted Yards per Pass. Asante Samuel's numbers were even more impressive. Since 2006, Samuel had been lower than 40th in the two charting stats only once: 2009, when he ranked 54th in Adjusted Yards per Pass. He was first in Adjusted Yards per Pass in both 2010 and 2011 before falling to 37th in 2012 after being traded to Atlanta.

Last year, both players saw their performance fall off. Cromartie's struggles were more about getting burned for huge pass plays; as you can tell from his average Adjusted Success Rate, he wasn't getting constantly beat both short and deep, just deep. You also might notice he was dead last in yards after the catch allowed, so he wasn't really getting much help from the safeties behind him. Samuel, on the other hand, completely fell off a bridge except for his weirdly low YAC allowed. The Falcons clearly saw what was up, as Samuel's snap count started dropping around Week 11 and the Falcons benched him for rookie Robert Alford in Week 14. The 33-year-old Samuel is now a free agent and nobody has shown much interest in signing him yet. Arizona signed the 30-year-old Cromartie and is hoping he can bounce back now that he will return to his previous role as "guy who plays on the other side of the shutdown corner."

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Robert McClain is a nice and perfect incapsulation of one of our recent mottos, which is "don't get fooled by small sample size nickelback stats." Brice McCain is the patron saint of this religion; maybe there's something in these guys' similar names? McClain was first in Adjusted Yards per Pass in 2012, and third in Adjusted Success Rate. Last year, he was bottom four in both stats. The moral of the story: Do not get overexcited by what a seventh-round pick on his third team does in a season of part-time performance.

Rookie Xavier Rhodes had nice stats for Minnesota last year (53 percent Adjusted Success Rate, only 5.9 Adjusted Yards per Pass) which is nice because as you can see above, that gives Minnesota a grand total of one quality cornerback. Their other corners have had poor stats for years.

There were a couple of veterans with surprisingly poor results in the game charting. Cromartie's results were surprising compared to his past performance, although everyone who watched the Jets realized he was struggling last season. Same goes for Ike Taylor with Pittsburgh. On the other hand, Brandon Flowers was a Pro Bowl alternate. Our charting stats suggest that nomination was made on reputation, not 2013 results.

Our stats also suggest that rookie nickelback Marcus Cooper did not quite live up to the public accolades he received. We're working on a new way to display "target rate" in this year's Football Outsiders Almanac 2014 which will be based on what percentage of team targets a cornerback faced adjusted for his snap count. It's a little too rough to run all the numbers here, but based on this method Cooper comes out as the most-targeted cornerback in the league, followed by Dee Milliner, Brandon Boykin, and last year's surprise Giants hero, Trumaine McBride. Weirdly, the least-targeted cornerbacks by this method include Cook and Robinson, the two struggling Vikings, along with Darrelle Revis, Richard Sherman, and for some reason Josh Wilson.

Next, we'll look at the top cornerbacks in Adjusted Success Rate

Worst Cornerbacks in Adjusted Success Rate, 2013 Player Team Charted

Targets Adj

Yd/Pass Rk Adj

Suc Rate Rk Avg. Pass

Distance YAC Rk 22-A.Samuel ATL 33 11.5 86 31% 87 14.5 2.6 9 21-J.Robinson MIN 45 10.2 81 35% 86 10.3 3.3 25 20-C.Cook MIN 43 10.5 82 35% 85 12.0 3.8 39 27-R.McClain ATL 53 11.3 85 37% 84 9.6 6.7 82 29-S.Wright SD 84 10.0 80 38% 83 14.1 4.7 66 21-M.Jenkins OAK 68 8.7 69 41% 82 11.2 4.3 56 25-K.Jackson HOU 76 8.5 66 42% 81 11.9 2.3 5 24-I.Taylor PIT 109 8.9 71 43% 80 12.7 4.1 50 27-J.Banks TB 69 8.8 70 44% 79 11.6 4.8 69 23-R.Alford ATL 55 8.2 59 45% 78 14.5 4.8 67 21-J.Jenkins STL 80 9.9 79 45% 77 12.0 6.0 81 22-D.Cox SD 59 9.4 78 46% 76 13.1 3.3 26 21-B.Grimes MIA 92 8.1 58 47% 73 13.4 3.5 33 20-P.Amukamara NYG 90 6.9 22 48% 68 11.0 2.9 16 26-C.Williams PHI 110 7.0 28 48% 67 13.4 3.3 23

Most of these names are the same as on the table for worst Adjusted Yards per Pass, with a handful of new names. Kareem Jackson's decline last year was a bit of a surprise after he had played so well in 2011 and 2012. Brent Grimes is another player whose Pro Bowl accolades aren't really supported by our coverage stats, although our stats had loved him when he was in Atlanta. Cary Williams is the Platonic Ideal of a cornerback who allows pass after pass to be completed right in front of him but rarely gets burned deep; Prince Amukamara had a similar season to Williams.

This final table is more for conversation than for any kind of evidence of which players were or were not very good this year. Allowing YAC often has more to do with the defensive scheme than with a cornerback's skill set. I wrote last week about DRC's ridiculously Ihenacho-enhanced YAC numbers.