Cornerbacks: Cover Snaps Count

| May 20, 2011

With the limits of television footage, it would be an accurate statement to say cornerback is the trickiest position for those outside of NFL teams to analyze.

That, however, hasn’t stopped the discussion and people are finding new ways to help us all better understand CB play. In recent years, advanced stats such as those provided by this site, have added to this. The use of stats such as pass break ups, times thrown at, and yards allowed have all contributed in this regard, but it’s always missing a degree of context.

Has a guy who has been thrown at 80 times and allowed 60 receptions necessarily been more of a target than a player who was thrown at 60 times and allowed 45 receptions? There’s an important piece of information missing and it’s this extra level of context that we search for at Pro Football Focus, aiming to enhance discussion on all things NFL.
 

So, by way of our game analysis process, we’re bringing you something that will push things a step further. A simple enough premise, we’ll look at how often a cornerback is thrown at and how many receptions he allows compared to how many snaps he has spent in coverage.
 
Up first, we’re checking out the percentage of plays in coverage that corners were thrown at. For this study we looked at all cornerbacks who were in coverage for at least 300 snaps (playoffs included), and it’s no surprise who has been targeted least often: Nnamdi Asomugha.
 
When it comes to having a reputation that QBs fear, there isn’t another player like the soon to be free agent. He was targeted on just 6.58% of the 441 plays he was in coverage. Perhaps more of a surprise is that Miami’s Sean Smith winds up in second place. There are some mitigating circumstances as Smith spent time in the safety spot in their third down nickel defense. Still, it’s reflective of the ability Smith has shown, though his inability to turn break-ups into picks impacts the common view on him.
 
Others in the Top 5 you would expect to see include Asante Samuel and Darrelle Revis. With Samuel, you worry about throwing the ball to him because he’s the kind of playmaker who can turn a game around in one play. Revis, on the other hand, allows so little that it’s not so much a risk to throw in his direction as it’s a pointless exercise. After 2009, where he was thrown at on a staggering 18.27% of plays he was in coverage, teams seemed to realize that was a foolish strategy and the number dropped to 10.32% in 2010 (even with him playing hurt part of that time).
 

Top 20 Cornerbacks, Times Thrown At per Coverage Snaps

Rank
Player
Team
Cover Snaps
Thrown At
TA/COV
1Nnamdi AsomughaOAK441296.58%
2Sean SmithMIA448449.82%
3Asante SamuelPHI4464610.31%
4Darrelle RevisNYJ5926711.32%
5Rashean MathisJAX5676611.64%
6Shawntae SpencerSF6227712.38%
7Chris GambleCAR3774712.47%
8Kelly JenningsSEA6257812.48%
9Sam ShieldsGB5436812.52%
10Vontae DavisMIA5667212.72%
11Joselio HansonPHI4505812.89%
12Leon HallCIN5637413.14%
13Ike TaylorPIT76310213.37%
14Champ BaileyDEN4896613.50%
15Quentin JammerSD5767813.54%
16Bradley FletcherSL6018213.64%
17Ronde BarberTB5157113.79%
18Charles WoodsonGB6589113.83%
19Corey WebsterNYG5768114.06%
20Kyle ArringtonNE5337514.07%

 

At the other end of the scale, we see some interesting names. Not too surprisingly given how often they’re likely to be targeted on shorter routes over the middle, a number of slot cornerbacks find themselves in the mix. There are, however, a number of starters ranking lowly as well. Players like Brent Grimes and Bryant McFadden both found themselves the guys in the firing line, though they dealt with it in different manners: Grimes managed to make plays on the ball, finishing second in pass deflections, while McFadden ended with a -6.1 grade in coverage.
 

Bottom 20 Cornerbacks, Times Thrown At per Coverage Snaps

Rank
Player
Team
Cover Snaps
Thrown At
TA/COV
64Antoine CasonSD56210017.79%
65Michael AdamsARZ3596417.83%
66Leodis McKelvinBUF4438018.06%
67Stanford RouttOAK5489918.07%
68Jabari GreerNO4989018.07%
69Greg TolerARZ5249518.13%
70Derek CoxJAX4017418.45%
71E.J. BiggersTB4388118.49%
72Alphonso SmithDET3466418.50%
73Bryant McFaddenPIT64212018.69%
74Javier ArenasKC3907418.97%
75Brent GrimesATL66812719.01%
76Orlando ScandrickDAL4017719.20%
77Drew ColemanNYJ3857419.22%
78Glover QuinHST60711719.28%
79Perrish CoxDEN4358419.31%
80Lardarius WebbBLT4348519.59%
81Terrell ThomasNYG61512420.16%
82Dimitri PattersonPHI4028420.90%
83Jerraud PowersIND3177824.61%

 

While it’s interesting to see who is targeted the most, it’s more relevant to look at how many receptions a cornerback allows while they are in coverage. In other words, you may be targeted a lot, but if they’re not resulting in anything, then so what. Revis’ 2009, as an example.
 
In something that will come less of a surprise, up at the top again is Nnamdi Asomugha.  Even when quarterbacks get brave enough to throw at him, it’s not likely to end up in a completion.  Similar stories for Asante Samuel and Darrelle Revis, with the most interesting stories coming from guys making this top ten list after not making the targets per coverage snaps list.
 
Despite being targeted on 15.53% of plays he was in coverage, Green Bay’s Tramon Williams allowed a reception on just 7.07% of plays he was in coverage.  Similarly, Josh Wilson moved from 43rd in terms of how much he was targeted, to ninth in terms of receptions allowed when looking at how many snaps he was in coverage.
 

Top 20 Cornerbacks, Receptions Allowed per Coverage Snaps

Rank
Player
Team
Cover Snaps
Receptions Allowed
REC/COV
1Nnamdi AsomughaOAK441132.95%
2Asante SamuelPHI446214.71%
3Darrelle RevisNYJ592284.73%
4Sean SmithMIA448245.36%
5Rashean MathisJAX567396.88%
6Quentin JammerSD576406.94%
7Bradley FletcherSL601426.99%
8Tramon WilliamsGB792567.07%
9Josh WilsonBLT451327.10%
10Sam ShieldsGB543397.18%
11Brandon CarrKC700517.29%
12Kelly JenningsSEA625467.36%
13Tim JenningsCHI621467.41%
14Ike TaylorPIT763577.47%
15Corey WebsterNYG576447.64%
16Stanford RouttOAK548427.66%
17Chris GambleCAR377297.69%
18Champ BaileyDEN489387.77%
19Leon HallCIN563447.82%
20Vontae DavisMIA566457.95%

 

Meanwhile, those suffering the biggest drops include Richard Marshall who went from 53rd in targets per coverage snaps, to 78th in receptions allowed per snaps in coverage. Some of this is down to Marshall moving inside in nickel situations (a study we’ll be looking to do in the future), but it remains an alarming fall, and not in line with other starting cornerbacks who move into the slot in their team’s sub package such as Charles Woodson or Ronde Barber.
 

Bottom 20 Cornerbacks, Receptions Allowed per Coverage Snaps

Rank
Player
Team
Cover Snaps
Receptions Allowed
REC/COV
64Fabian WashingtonBLT3123511.22%
65Eric WrightCLV3824311.26%
66William MiddletonJAX3193611.29%
67Johnathan JosephCIN3714211.32%
68Michael AdamsARZ3594111.42%
69Jacob LaceyIND4004611.50%
70D.J. MooreCHI4465211.66%
71Jabari GreerNO4985911.85%
72Glover QuinHST6077312.03%
73Alterraun VernerTEN6047312.09%
74Lardarius WebbBLT4345312.21%
75Terrell ThomasNYG6157612.36%
76Alphonso SmithDET3464312.43%
77Bryant McFaddenPIT6428112.62%
78Richard MarshallCAR5777312.65%
79Drew ColemanNYJ3854912.73%
80Javier ArenasKC3905012.82%
81Dimitri PattersonPHI4025313.18%
82Orlando ScandrickDAL4015313.22%
83Jerraud PowersIND3175116.09%

 

Of course, these aren’t numbers you can blindly look at and say that because a player is being targeted less, or allowing fewer receptions he’s a better player. There are a number of other factors to consider. Take the cornerbacks of the NFC West for example, are you really going to say their receptions allowed per time in coverage doesn’t benefit from having a division somewhat lacking in quality QB play? Or that a cornerback playing for the Packers doesn’t benefit from their high sack count. Then, of course, there are players who are targeted more because their teammates are just that good.
 
When Champ Bailey’s Bronco partner Perrish Cox was in the lineup, teams went after him.  Oakland’s Stanford Routt was targeted on 18.07% of all plays with teams looking at him as a safer option than Asomugha. Dunta Robinson’s contract seemed to scare people into believing he was better than he performed, with the playmaking Brent Grimes the guy seeing more action.
 
Let’s pause on Grimes for a minute, he’s an interesting one. Targeted on 19.01% of the plays he dropped into coverage (74th out of 83), he only allowed receptions on 10.03% and finished second in the league in combined pass deflections and interceptions. Top it with a +7.5 coverage grade, and you have to think that next year teams may shy away and start looking more towards Robinson (who didn’t perform badly, but didn’t exactly earn his mega contract).
 
Looking from the opposite point of view, maybe you’ll expect Shawntae Spencer (targeted on just 12.38% of plays in coverage) to get more treatment after allowing 70.1% of the balls thrown his way to be completed (part of what earned him a -4.5 coverage grade).
 
Ultimately, these numbers are a little offseason fun. They tell us some things we already knew (teams don’t throw at Asomugha, Samuel and Revis if they can help it) and some things we didn’t (they also don’t throw at Rashean Mathis, Sean Smith and Bradley Fletcher).
 
The real value in them is that they add to the discussion about cornerback play.  You can’t truly judge a cornerback and his metrics, without looking at how many times he dropped into coverage.  Even that doesn’t offer as much as grading, but as said, it just adds more context to the debate.
 
So take these number under advisement, but don’t jump to conclusions over all of them … though it is fair to say that Scrabble remains a game quarterbacks don’t like to play.
 
______________
 

We’ll leave you with one further look. Combining the tables above to we can illustrate a mashed-together view of each qualifying corner’s times beaten (receptions allowed), times challenged (thrown at), and challenge opportunities (snaps in coverage) – effectively, catch % per cover snap.
 
Asomugha doesn’t rule this one, as he ranks relatively lower on challenges and challenge opportunities. Players that managed to keep their catch percentage under 50% while racking up higher coverage snap counts like Tramon Williams, Brandon Carr, and Antonio Cromartie benefit.
 
The number itself is rather odd to look at and could be tweaked to be more glance-friendly, but here it is in raw form:
 

Top 20 Cornerbacks, Catch Percentage per Coverage Snaps

Rank
Player
Team
Receptions Allowed
Thrown At
Cover Snaps
Catch% per Cover Snap
1Tramon WilliamsGB561237920.0575%
2Brandon CarrKC511117000.0656%
3Antonio CromartieNYJ551156830.0700%
4Darrelle RevisNYJ28675920.0706%
5Ike TaylorPIT571027630.0732%
6Stanford RouttOAK42995480.0774%
7Brent GrimesATL671276680.0790%
8Charles TillmanCHI671117510.0804%
9Brandon FlowersKC551096250.0807%
10Tim JenningsCHI46916210.0814%
11Devin McCourtyNE581046850.0814%
12Bradley FletcherSL42826010.0852%
13Chris CarrBLT621006990.0887%
14Quentin JammerSD40785760.0890%
15Antoine CasonSD521005620.0925%
16Cortland FinneganTEN701057130.0935%
17Charles WoodsonGB56916580.0935%
18Corey WebsterNYG44815760.0943%
19Kelly JenningsSEA46786250.0944%
20Ronald BartellSL50965480.0950%

 

Bottom 20 Cornerbacks, Catch Percentage per Coverage Snaps

Rank
Player
Team
Receptions Allowed
Thrown At
Cover Snaps
Catch% per Cover Snap
64Tracy PorterNO43664340.1501%
65Carlos RogersWAS50724620.1503%
66Dimitri PattersonPHI53844020.1570%
67Chris GambleCAR29473770.1637%
68D.J. MooreCHI52714460.1642%
69Aqib TalibTB35593570.1662%
70Orlando ScandrickDAL53774010.1716%
71Drew ColemanNYJ49743850.1720%
72Kelvin HaydenIND38583800.1724%
73Eric WrightCLV43653820.1732%
74Javier ArenasKC50743900.1733%
75Johnathan JosephCIN42643710.1769%
76Michael AdamsARZ41643590.1784%
77Jason McCourtyTEN31523220.1851%
78Justin TryonIND38603420.1852%
79Jacob LaceyIND46624000.1855%
80Alphonso SmithDET43643460.1942%
81Jerraud PowersIND51783170.2063%
82Fabian WashingtonBLT35513120.2200%
83William MiddletonJAX36493190.2303%

 
 

  • http://www.mastertour.org fedetn

    Let’s pause on Grimes for a minute, he’s an interesting one. Targeted on 19.01% of the plays he dropped into coverage (74th out of 83), he only allowed receptions on 10.03% and finished second in the league in combined pass deflections and interceptions. Top it with a +7.5 coverage grade, and you have to think that next year teams may shy away and start looking more towards Robinson (who didn’t perform badly, but didn’t exactly earn his mega contract).

    i love Grimes!

    • james carbone

      I also really like Grimes. He deserved a lot more attention then he received for the way he played. Can’t imagine the falcons letting him get away, but if he isn’t signed to a long term deal, I’d love for Philly to pick him up.

  • tenotnamedmiller

    So CHI Tillman and Jennings were pretty much the same in catches allowed? Teams were picking at Jennings like he was a scab. But I guess # say different story.

    • Rick Drummond

      Counting playoffs here, Jennings allowed completions on roughly 50% of targets his way, Tillman roughly 60%, and Tillman was targeted 20 more times. Factoring in Tillman’s 130 more cover snaps evens things up a bit (in that final set of tables).

  • trippieg

    I’d like to see this expanded on with a metric beyond passes completed. The problem with the last two tables is that the top 20 is loaded with teams that play aggressive man coverage (NYJ, OAK), and the bottom twenty is full of players who play in zone coverage defenses (all four IND corners, as well as anyone who covered primarily out of the slot).