Rise of interior defenders forces change in IDP fantasy strategy

As team strategy changes, fantasy strategy has to adjust as well. As Sean Kirby notes, that change is biggest right now in IDP.

| 11 months ago
(Joe Robbins/Getty Images)

(Joe Robbins/Getty Images)

Rise of interior defenders forces change in IDP fantasy strategy

In 2016 IDP drafts, it’s common to see the first handful of defensive linemen selected from the interior defender pool. In fact, this subset of defensive linemen has been climbing the IDP ranks at a remarkable rate over recent years. IDP fantasy football has come a long way since the days when everyone attempted to start a right defensive end from a 4-3 defense. Changes in the NFL have resulted in increases in the number and caliber of 3-4 defensive ends and defensive tackles.


The term “Interior defenders” refers to defensive tackles and 3-4 defensive ends. On the other hand, “edge defenders” are 4-3 defensive ends and 3-4 outside linebackers. We can’t use 3-4 outside linebackers as defensive linemen for fantasy, so they won’t be discussed much here. Designations are based on the base defense, a problematic practice recently discussed by Jeff Ratcliffe.

Historically, edge defenders have outproduced their interior counterparts in fantasy, largely as a result of higher sack counts. Therefore, it may be surprising to see that the PFF Draft Guide splits the top 10 evenly, with five 4-3 defensive ends and five interior defenders.

Top 10 Fantasy Defensive Linemen (PFF Draft Guide IDP top 150 overall rank)
4-3 Defensive Ends Interior Defenders
Carlos Dunlap (8) J.J. Watt (1)
Robert Quinn (10) Aaron Donald (9)
Ezekiel Ansah (17) Muhammad Wilkerson (14)
Everson Griffen (19) Calais Campbell (18)
Khalil Mack (25) Fletcher Cox (22)

Rise of the Interior Defender

The ranking looks less outlandish when you look at recent trends at the positions. Specifically, interior defenders have been generating much more pressure recently. In fact, 2015 marks the first year that top-10 interior defenders surpassed 4-3 defensive ends in average quarterback pressures.

Graph 1

Sacks vs. Pressures

Why do we care about quarterback pressures when hits and hurries don’t generate fantasy points? Sacks are such rare events that they are subject to sample bias. Quarterback pressures provide a more robust representation of a player’s pass-rushing productivity. Additionally, quarterback pressures definitely correlate closely with sacks on a large scale. The following graph illustrates the correlation. As interior defenders register more quarterback pressures, they generate more sacks.

Graph 2

Without Watt

The ascension of interior defenders definitely coincides with the rise of J.J. Watt. He’s an outlier in many ways, but removing him from the analysis doesn’t diminish the trend (graph below). You might make a similar argument that Aaron Donald, Kawann Short and Fletcher Cox are also outliers at their position. At some point, outliers become a trend and we are well past that point. High-ceiling interior defenders are abundant and a mainstay of all IDP formats until proven otherwise.

Graph 3

The Name Game

While it’s clear that “interior defenders” are generating more pressures and sacks, it’s unclear how much of it is actually happening from the interior. There does seem to be a an increasing group of true disruptive interior pass rushers, anchored by Aaron Donald, Geno Atkins and Fletcher Cox, among others. However, in a league where versatility has become highly desirable, many players aren’t categorized easily. For instance, Watt and Muhammad Wilkerson were top-five “interior defenders,” who actually spent the majority of their 2015 snaps as outside LEO rushers. A significant portion of the increased production by interior pass rushers is certainly the result of our worsening ability to accurately categorize these individuals. Now more than ever, it pays to know how your defensive lineman is utilized in his defensive scheme.

2016 implications

Last year was the first time NFL teams running a 3-4 base defense outnumbered those running a 4-3. While the division is somewhat arbitrary, it has drastic fantasy implications. With an increasing number of 3-4 outside linebackers removed from defensive line player pool, the IDP team owner will need to learn how to utilize interior defenders. Luckily, startable options are more plenty than ever. Here are a few of the non-Watt interior defenders that The PFF Draft Guide considers top-10 defensive linemen for IDP fantasy football.

Aaron Donald, Los Angeles Rams: Donald finished second in most scoring formats in 2015. As a young developing player, it’s tempting to expect even more from his third year. However, it’s worth noting that he needed to break PFF’s grading scale to reach these heights. He was by far the highest-graded player in 2015 at any position, surpassing second-place Khalil Mack by more than 15 points. Donald’s 2015 campaign was likely very near the absolute ceiling for an interior defender. While well-above-average tackle counts made him an elite fantasy option, he only finished eighth in sacks. I project Donald as the most consistent high end DL1 over the next decade. However, he is unlikely to ever create his own tier far above the rest of the class, as Watt has done for the past several years.

Muhammad Wilkerson, New York Jets: Like Watt, Wilkerson benefits from a mix of interior and outside opportunities. It’s allowed him to be a top-10 defensive lineman four straight years (after correcting 2014 for injury). Things should continue similarly under Todd Bowles, as Wilkerson is the current New York Jet most likely to replicate Calais Campbell’s role. In the very short term, he’s currently recovering from a leg injury, but is expected to be recovered in time for the regular season.

Calais Campbell, Arizona Cardinals: As a top defensive lineman since 2010, Campbell was a harbinger of things to come for interior defenders. He hasn’t fallen outside the top 20 in our balanced scoring over that time and entered the top 10 with regularity. However, he’s only cracked double-digit sacks once (11 sacks, 2013), attesting to a definite ceiling on his production. At 29 years old, he has a few more years of consistent DL1 production.

Fletcher Cox, Philadelphia Eagles: Like Aaron Donald, Cox is a true interior defender. In fact, your host site likely even lists him as a defensive tackle after Philadelphia’s shift to a 4-3 base. In leagues that require defensive tackles specifically, Cox gets a huge boost. Defensive tackle is a hard spot to generate consistent points. His sack potential gives you a major advantage against other defensive tackles. There is some uncertainty about how 2016 will shake out for the Philadelphia defensive line, with Vinny Curry and Brandon Graham competing for opportunities on the outside.

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