Stat of the Day: 2009 CB Charting Stats II

by Aaron Schatz

As part of our ongoing Stat of the Day series, we've spent the past four weeks digging deep into our spreadsheets to run a new stat every weekday until Super Bowl XLIV (well, until today... this is going to be the last one, so that the Super Bowl preview can get everybody's full attention tomorrow).

Yesterday [1] we took a look at the best cornerbacks of the season according to the FO game charting project. Today, we'll flip things around and look at the corners who rank at the bottom of the game charting stats. I've ranked all cornerbacks with at least 40 charted passes, which means 70 total cornerbacks. 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, and pass interference is not yet included.

Typical caveats apply, of course: This is imperfect data based on the game charting project, which means it comes off limited television camera angles. In past years, this data has been very inconsistent from year to year, and we're going to study that in the offseason to try to figure out if we can get more accurate numbers by, say, looking at players over two-year spans.

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.

Bottom 10 Cornerbacks in Success Rate, 2009 (data as of 2/3/10)
Player	Team	Charted Targets	Yd/Pass	Rk	Avg. Pass Distance	YAC	Rk	Success Rate	Rk
20-N.Harper	TEN	63	8.8	61	9.4	3.2	24	38%	70
23-M.Trufant	SEA	55	9.6	65	13.0	4.9	62	40%	69
23-T.Jennings	IND	65	6.4	18	10.1	1.8	4	42%	68
21-V.Davis	MIA	47	12.6	70	12.7	6.0	67	43%	67
24-R.Bartell	STL	61	9.5	64	12.5	4.7	56	43%	66
31-F.Washington	BAL	42	11.6	69	11.9	6.4	69	43%	65
23-C.Houston	ATL	51	8.4	58	14.0	1.8	3	43%	64
26-K.Hayden	IND	48	8.1	54	11.9	2.9	20	44%	63
27-M.Jenkins	NO	41	10.0	67	11.2	6.4	68	44%	62
35-Z.Bowman	CHI	54	8.2	55	13.1	2.8	16	44%	61

At what point have we compiled enough data showing that Marcus Trufant [2] came back from a back injury far below 100 percent health? Not only is he near the bottom in the charting stats, he also managed to get penalized for defensive pass interference seven times in just ten games.

You may notice some players on this list who will be appearing in the Super Bowl this Sunday. Tim Jennings [3] is here because of the Colts' defensive philosophy: prevent the big play, even if it means allowing a first down. Malcolm Jenkins [4] is here because he was god awful as a rookie. Kelvin Hayden [5] is probably some mix of the two -- he's been better than this in previous years, and I'm a little surprised to see his stats so low. (Maybe this is just a product of the year-to-year inconsistency of the charting stats; as I say above, we're going to study it in the offseason.)

Bottom 10 Cornerbacks in Yards per Pass, 2009 (data as of 2/3/10)
Player	Team	Charted Targets	Yd/Pass	Rk	Avg. Pass Distance	YAC	Rk	Success Rate	Rk
21-V.Davis	MIA	47	12.6	70	12.7	6.0	67	43%	67
31-F.Washington	BAL	42	11.6	69	11.9	6.4	69	43%	65
24-S.Smith	MIA	49	10.1	68	15.8	4.3	50	59%	11
27-M.Jenkins	NO	41	10.0	67	11.2	6.4	68	44%	62
22-B.McDonald	CLE	56	9.7	66	13.3	7.0	70	57%	19
23-M.Trufant	SEA	55	9.6	65	13.0	4.9	62	40%	69
24-R.Bartell	STL	61	9.5	64	12.5	4.7	56	43%	66
24-J.Wilhite	NE	53	9.4	63	13.8	3.8	42	49%	51
21-D.Cox	JAC	86	9.2	62	12.9	2.9	18	47%	55
20-N.Harper	TEN	63	8.8	61	9.4	3.2	24	38%	70

This mix is a pretty good mix of the old (Nick Harper [6]), the slowed by injury (Trufant), and a lot of rookies and near-rookies (pretty much everyone else). The exceptions are Ronald Bartell [7], who's never had good numbers and isn't exactly getting help from a good pass rush in St. Louis, and Fabien Washington [8], whose really poor charting numbers are a bit of a mystery to me. I've always thought of him as average, not terrible.

The numbers for Brandon McDonald [9] and Sean Smith [10] are particularly interesting, since they end up as mirror-universe counterparts to the Colts cornerbacks. You might remember McDonald from his adventures getting completely toasted by the Denver Broncos on an NFL Network broadcast, Thanksgiving evening in 2008. His numbers from 2009 show he did a much better job of coverage overall, but he's still toaster-friendly. When you beat Brandon McDonald [9], you really beat Brandon McDonald [9]. He is listed as DEFENDER1 on five passes of 40 or more yards, including a 72-yard Derrick Mason [11] touchdown. (The charter did mark that one as double coverage, with Abram Elam [12] as the deep safety help who also got beat.) Miami rookie Smith had an even better Success Rate than McDonald, but gave up three passes over 40 yards and another three between 30 and 40 yards.

Bottom 10 Cornerbacks in YAC Allowed, 2009 (data as of 2/3/10)
Player	Team	Charted Targets	Yd/Pass	Rk	Avg. Pass Distance	YAC	Rk	Success Rate	Rk
22-B.McDonald	CLE	56	9.7	66	13.3	7.0	70	57%	19
31-F.Washington	BAL	42	11.6	69	11.9	6.4	69	43%	65
27-M.Jenkins	NO	41	10.0	67	11.2	6.4	68	44%	62
21-V.Davis	MIA	47	12.6	70	12.7	6.0	67	43%	67
22-A.Samuel	PHI	53	8.1	53	10.5	5.6	66	55%	29
23-C.Griffin	MIN	51	8.1	52	10.6	5.5	65	53%	38
20-C.Gamble	CAR	49	8.4	57	9.3	5.0	64	45%	58
24-S.Brown	PHI	72	7.2	36	12.0	4.9	63	63%	6
23-M.Trufant	SEA	55	9.6	65	13.0	4.9	62	40%	69
22-T.Porter	NO	68	6.3	15	11.7	4.9	61	54%	33

Can someone please teach the Philadelphia cornerbacks to tackle better? Thanks.