Greg Peshek

All Star Circuit

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Peshek: CB Metrics 2.0

Wednesday, February 12, 2014


This group of corners is a bit more of a mixed bag than last week’s. Kyle Fuller didn’t play a full season, but his stats in the time he did play were too tantalizing to leave out. On the other hand there’s a lot of data on Lamarcus Joyner, but many have questioned his role at the next level. Is he a corner, a safety, or a Tyrann Mathieu type hybrid. We’ll explore those players and a few others in this piece.


All numbers are hand charted by me. Because a target or ‘burn’ may be a bit subjective, the numbers won’t always line up with other stat services. However, I’ve used the same criteria for each player which means we can at least compare these stats to each other on an objective basis.


Archive:

QB Metrics featuring Teddy Bridgewater, Derek Carr, Blake Bortles and Johnny Manziel.

WR Metrics 1.0 featuring Sammy Watkins, Mike Evans, Marqise Lee and Kelvin Benjamin.

WR Metrics 2.0 featuring Brandin Cooks, Jordan Matthews, Jarvis Landry, Odell Beckham and Allen Robinson.

CB Metrics 1.0 featuring Darqueze Dennard, Jason Verrett, Terrance Mitchell, Bradley Roby and Justin Gilbert



The Trinity of CB Stats


These are what I like to call the trinity of CB stats. Burn rate, which is the number of completions against a defensive back divided by the total number of targets (the number below is adjusted for screens and pass interference). PD Rate which measures how often a DB gets their hands on the ball – a PD rate of 5 would mean the DB defenses the ball once every 5 targets. Finally Snaps/ Targets describes how often the DB is thrown at – the lower the number the more often a DB is targeted.


Tri  

- Fuller’s metrics here instantly stand out. His pass defense rate, where he gets his hands on one out of every 3 targets, is best for second in the two tiers behind only Jason Verrett. He was targeted more often than every other CB, but his leading burn rate of 24% more than makes up for it. With that stat, he edges out Darqueze Dennard for the least burned CB in this class.

 

- Similar to Fuller, Victor Hampton has a quality PD rate, but his burn rate is nearly double that of his fellow CB. Beat on 51% of all his targets, he was burnt more than any ‘traditional’ CB in the class.


- Ranking as one of the bigger surprises in this group is Purifoy’s burn rate of 33.3%. That rate beats first tier players such as Terrance Mitchell and Jason Verrett and comes in at second among both tiers. On the opposite side, his pass defense rate is second worst among both groups. Is that a result of quality coverage that didn’t result in QBs throwing many passes into tight coverage?


- For all the hype about Stanley Jean-Baptiste, finding that he was beat on 48.7% of all his targets is pretty disappointing. If you’re looking for positives, you could note that he wasn’t targeted particularly often which could be indicative of QBs only looking to him when the WR had good separation.


- Joyner is the odd man out in these. For a cornerback a burn rate of 55% would be rather appalling. However if you’re comparing him against a safety who lined up in the slot like Kenny Vaccaro from last year, it’d be a quality metric. That metric combined with his low target rate suggest a hybrid role may be more appropriate for him.



Where the Ball was Thrown?


This represents the total percentage of targets for each DB. Targets may not seem important when you can look at YPA/YPC, but it’s important to know if those are being skewed by a number of short or long throws. Green represents a below-average amount of targets while red represent an above-average number of targets. One isn’t better than the other, that’s just the scale I’m using.


Target  

- Kyle Fuller’s distribution is pretty normal except for an increased percentage of targets in the intermediate zone of 11-20 yards. This could either be a bad thing if he’s getting beat by NFL type throws or positive if he defended them well.


- In an interesting distribution chart, Victor Hampton was targeted pretty heavily in the 11-20 yard zone, but then was rarely challenged deeper than that. It’s possible that’s a result of quality coverage which we’ll check on in the next section.


- We see nearly an opposite phenomenon with Purifoy where he was only targeted 11% intermediately, but nearly 41% of his targets came deeper than 20 yards. You’d expect quality coverage downfield with the speed Purifoy displays.


- Joyner’s array of targets makes a lot of sense for a slot type corner/ safety. He was challenged heavily on shorter patterns, while seeing deep throws less than average 17% of the time.



How Did the DBs Defend Those Throws?


The completion percentage and target charts are essentially linked. It’s doesn’t matter if someone is getting beat 100% of the time if that only represents 5% of their total targets. Green is representative of an above-average completion percentage meaning that the DB defends those zones better than average. Red, of course, means their completion percentage is worse than average.


Comp  

- The 100% completion percentage on short passes for Fuller may look concerning, but it’s likely a product of the coverage at Virginia Tech. Fuller often played 6-10 yards off the LOS, ceding shorter throws to the opponent. More impressive here is that Fuller only gave up 7.14% of targets in the 11-20 yard zone. That means he was challenged 14 times and beat only once on those NFL type throws.


- The fact that Purifoy didn’t let one completion in the 1-5 yard zone is certainly a testament to his short area quickness. Although we have to be a concerned with the fact that he was beat on 45% of his deep targets. How’s his size going to fare against bigger, fast receivers?


- Stanley Jean-Baptiste has one of the strangest charts I’ve seen. He was only beat 33% of the time in the short zone (where he should be getting beat more) and then got beat on 77.8% of the time on deep passes. If I had to guess, his press ability and length helped to defend the short ball, while those same things may have given him trouble keeping up with faster, deep receivers.


- Failing to get beat once deep, Joyner displayed excellent ability against both short and long passes. Potentially more evidence for playing a hybrid role like many have discussed.



Where Did They Line Up?


This chart represents the technique the defensive back was playing at the start of the play. It’s been simplified down, so press-bail may not represent exact press-bail technique but situations where the DB didn’t get his hands on the WR. This can give you a feel for the experiences of each DB. These don’t tell you about their success playing these, but just the amount they played them.


Align  

- As mentioned earlier, Fuller played nearly 57% of his snaps 6-10 yards off the line of scrimmage. Although this led to many short completions, his quickness allows him to play off the ball and still make plays.


- Hampton also played of the ball quite a bit, nearly 51% of the time. However, it didn’t work out as well for him as it did Fuller. While playing off, he still allowed below-average completion percentages in the intermediate and deep zones.


- With a good mix of alignments, Purifoy played press 31.4% of the time. He still had experience lining up in off coverage another 50% of the time.


- Jean-Baptiste didn’t line up in press as much as you’d expect for someone with his size, dong so 28.4% of the time. However, the numbers suggest that he wasn’t any more or less proficient at defending when pressing the receiver.


That’s the extent of the stats here, there are a few more minor stats that I’ve left out for the sake of brevity. I’ll tweet out those and answer any questions on Twitter@NU_Gap. Thanks for reading.





Email :Greg Peshek



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