Fantasy: Tucking the Trend - Defensive Linemen Sack Evaluation

It goes without saying that we would all love to own a defensive lineman who puts up monster tackle numbers, but the fact of the matter is that a bulk of our points from this position will come from sacks (especially if you’re using the PFF IDP scoring system). Shameless plug out of the way, I want to take a look at how we can potentially identify players who will give us a better chance of accumulating those valuable sacks.

For the 2010 season, the staff here at ProFootballFocus.com has Jason Babin as the sack leader among defensive linemen with 14 sacks. Dwight Freeney finished the season five sacks behind Babin. On the surface it sounds like Babin had a much better year than Freeney, but looks may be deceiving. Sacks are certainly the product of skill, but there’s also a bit of luck involved. So if we just look at a player’s raw sack total, we can potentially be misled.

Sacks are ultimately a matter of opportunity. The more cracks a player has at the quarterback, the greater the likelihood that he will record a sack. A good indicator of opportunity is quarterback interruptions (QBI). This is the sum of sacks, QB hits, and QB pressures.

Again, like raw sack totals, it can be problematic to simply compare raw QBI totals. Julius Peppers and Mario Williams both tallied 60 QBIs last season, but Peppers played in 153 more snaps than Williams. Furthermore, we need to consider that QBIs occur on pass rushing snaps, which Peppers saw 94 more than Williams. To gain a better sense of how often each player had an opportunity to sack the QB, we can divide the QBIs by pass rush snaps to get each player’s QBI frequency. When we do, we can see that Williams at 13% actually was getting to the QB more frequently than Peppers at 11%.

QBI frequency will now give us a sense of opportunity, but it won’t tell the whole story. We also need to consider how often a player records a sack per QBI. Remember that luck factor I mentioned a few paragraphs ago? Well here’s where that comes in to play. In looking at the data from the last three seasons, no defensive lineman with a QBI total of 20 or higher had a QBI frequency above 18% (John Abraham tops the list with 18% in 2008), and no lineman was lower than 4%. The range of sacks per QBI, however, was not so close. Over the same span of time, there is a low of 0% (recorded by three players) and a high of 42% by Carlos Dunlap last season.

Because of this obvious disparity, I thought it might be a beneficial exercise to take luck out of the equation and look at last season’s QBI and sack data with every player on equal footing. To do so, I took my sample of defensive linemen over the last three seasons and calculated the average sacks per QBI frequency. I found that defensive linemen recorded a sack on an averaged of 15.9% of their QBIs. So if we apply this average to each player’s QBI total, we get an adjusted sack total.

Underachievers

Chris Long – St. Louis

Despite recording the second most QBIs (78) among defensive linemen, Long managed a sack on only 10.3% of them. When we apply the average sack frequency to his QBIs, his sack total jumps from eight to twelve. Long’s QBI frequency of 13.5% sits well above the 9.8% average of the sample, so expect him to continue to get to the QB in 2011. Also expect his sack frequency to regress closer to the average, which means a double-digit sack total.

Kroy Biermann – Atlanta

Among the players I sampled, Biermann had one of the lowest sack frequencies at just 6.3% in 2010. The opportunities certainly were there, as he recorded 48 QBIs at a clip of 11.7%, but luck just wasn’t on his side. When we adjust his stats, his sacks total moves from three to eight, which would vault him into the conversation of fantasy relevance. Biermann is an excellent candidate to keep on your radar as a late-round pick who has the potential to offer big value.

Antonio Smith – Houston

I have to admit that this one really surprised me when I ran the data, but Smith was a huge underachiever in 2010. His QBI total of 64 ranked ninth among defensive linemen, and actually tied him with Jason Babin in this category. At the same time, Smith managed the fifth lowest sack frequency (4.7%) among defensive linemen with at least 20 QBIs. Adjusted, his total jumps an astonishing seven sacks from three to ten. I wouldn’t put too much stock in this adjustment, however, as the Texans are moving to a 3-4 under new defensive coordinator Wade Phillips. Smith last played in the 34 in Arizona. In 2008, his final season with the Cardinals, Smith recorded just 27 QBIs in 439 pass rush snaps.

Overachievers

Carlos Dunlap – Cincinnati

As I pointed out earlier, Dunlap’s sack frequency of 41.7% was well above the sample average of 15.9%. Though no doubt anomalous, this frequency was also the product of Dunlap mainly being used on third downs in obvious passing situations. In fact, 75.3% of Dunlap’s 287 snaps occurred in pass rush situations. With the frequency adjustment to the average, Dunlap drops from ten sacks down four. Though I expect him to see more snaps this season, I would be cautious with expectations for Dunlap and would not want to rely on him as my DE1.

Ndamukong Suh – Detroit

Suh is a specimen. But when a DT posts double-digit sack numbers, we’re likely looking at an overachiever. Suh’s 2010 sack frequency of 26.8% makes him one of only 17 players to top 25% in the last three seasons. Am I saying that Suh can’t repeat this performance in 2011? Not necessarily. It could happen, but none of the eleven players who topped 25% in 2008 and 2009 accomplished this feat the following season. Regressed to the average, Suh’s sack total drops to seven. This is still impressive for a DT, but is not the dominant numbers he posted in 2010.

Jason Babin – Tennessee

It should come as no surprise that Babin overachieved in his 2010 campaign. Nearly half of Babin’s career sack total came last season. That’s an eight-year career. While it could be argued that Babin has matured and that he peaked last season, his 21.9% sack frequency suggests he may also have gotten a little lucky too. Adjusted, his sack total drops to ten, which is still a nice number from your DE. That being said, I would be reluctant to rely on Babin as my DE1 in 2011. His 2010 overachieving and uncertain future are both cause for concern.

The Exception

Justin Tuck – New York Giants

In doing my analysis I noticed that one player kept bucking the trend – Tuck. Over the past three seasons, Tuck has posted a sack frequency of 25.5%, 24.2%, and 23.6%. While multiple defensive linemen have topped 20% in two of the last three seasons, Tuck is the only to top that mark in all three seasons.  This remarkable consistency leads me to expect Tuck to continue his dominance in 2011. Accordingly, I have him projected as the hands down top defensive linemen.

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