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J.J. Watt
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By The Numbers

NFL Draft Analytics for DEF

by Hayden Winks
Updated On: February 19, 2019, 1:48 am ET

In this column, we are going to find which college and NFL Combine statistics have been correlated to early NFL success, which I’m measuring using Pro Football Reference’s Approximate Value (AV) statistic. However, I’m only looking at the per game AV (AV/G) in NFL seasons two through four because rookie players often don’t perform and teams see the most return on their picks in the latter portion of their rookie contracts.


If you aren’t familiar with correlations here is a brief overview: The chart below will look complicated, but it’s really not. The left side of the chart is the college stats, and the top of the chart is the NFL stats. The darker the color (either green or red) the more correlated the two stats are. If there isn’t a lot of color in the cell, then the two stats have little to zero relationship. The numbers shown in the chart are correlation coefficients. If you want R-squared, just square the number. I chose correlation coefficients to show positive and negative correlations with color. Here’s a short video if you’re confused.


EDGE (Under 270 pounds)



These are your speed rushers, and it shows in the NFL Combine stats. The most correlated stats with AV/G are the cone drill, speed score, 40-yard dash, and agility score. And all of them are measurements of speed. If your trying to predict Pro Bowls, then speed score is the top metric.


Of the on-field college metrics, there isn’t a single statistic that has been correlated to overall early NFL success. Instead, we need to go NFL statistic by NFL statistic. For example, let’s look at NFL sacks per game, which is the primary statistic NFL teams are looking for when they draft an EDGE rusher. There are two college stats that have historically been correlated with NFL sacks per game -- tackles for loss and tackles for loss per game.



That means that by simply weighting college tackles for loss over college sacks, you’ll have an advantage over other draft analysts. In fact, 15 of the 17 EDGE rushers who averaged at least 0.50 sacks per game in NFL seasons two through four averaged at least 1.0 tackles for loss in his final collegiate season.


EDGE (Over 270 pounds)



A lot of the same things that we just went over can be extended to the 270-plus pound EDGE rushers, but there are differences. Of the NFL Combine metrics, the cone drill, broad jump, and agility score are still important, but speed score and the 40-yard dash aren’t as correlated to early NFL success. This makes sense because these heavy EDGE rushers are more reliant on power and hand usage than the speed rushers.



However, speed does still matter for the big boys, especially when it comes to sacks per game. The six heavy EDGE rushers who averaged more than 0.50 sacks per game in NFL seasons two through four all had a cone drill under 7.26 seconds. That’s the current threshold for elite pass rushers who step on the scale at over 270 pounds.


Of the on-field college statistics, there’s one really large surprise -- college pass deflections appear to be important, but that’s solely because of J.J. Watt. If I remove him from the sample, there’s zero correlation. Instead, I’ll be focusing on tackles for loss again. But it’s just less important for the heavier EDGE rushers compared to the sub-270 pounders.