http://www.rotoworld.com/articles/nfl/69311/72/position-review-pass-rushers
Khalil Mack
The Raiders’ pass rusher was a hot topic last offseason and it looks like that will continue. The signing of
Bruce Irvin, who made a name for himself at SAM linebacker in Seattle’s 4-3 "under" defense, brought a scheme change to the Raiders and a huge IDP value increase to Mack. It was a highly-debated topic since the Oakland front seven runs a variety of alignments, but it was accurately predicted last season that the Raiders would run 4-3 "under" on most of their plays.
I charted every single play from the 2016 season, and in the first nine weeks the Raiders employed some type of 4-3 defense for 58% of their base snaps. This included 4-3 "under," which places Irvin on the line of scrimmage opposite Mack in a two-point stance next to a five-technique defensive end, in addition to 4-3 looks with Irvin covering slot receivers. There were also a few plays of standard 4-3 with Irvin as an off-ball strong-side linebacker. Everything was going great from an IDP perspective, but it didn't work well for the Raiders.
Oakland sported a 7-2 record entering its bye, but not because of the defense, which was constantly stomped by offenses to begin the year. In five of the first seven games, Oakland allowed opponents to produce at least 400 yards of total offense, two of which were over 500 yards. As the Raiders came out of their Week 10 bye, they made an obvious change: They were going to run more 3-4 looks.
Brace yourselves Mack owners. In Weeks 11-14, the Raiders used Mack at outside linebacker on 127-of-137 base snaps (92.7%) in a 3-4 alignment. This was not pretty for Mack's future IDP value, but it worked on the field. Mack ended up playing outside linebacker on 84% of snaps in eight games post-bye (including Oakland's Wild Card loss)
and the Raiders did not let a single opponent hit the 400-yard mark. An eye-popping stat is that in Week 5, the 4-3 Oakland defense surrendered 423 yards at home to the Chargers, yet completely dominated
Philip Rivers in a Week 15 matchup in San Diego while playing 3-4, allowing a season-low 262 yards.
Looking at the season as a whole, Mack played linebacker on 63% of base defensive snaps.
Mack's IDP position designation is far from safe, and all fantasy owners need to take note.
Add in the fact that the Raiders brought in 3-4 mind John Pagano as assistant head coach/defense, and it’s not only a
possible scenario that Mack will be moved to linebacker for IDP in 2017,
it’s the most likely one.
TL;DRP version - the defense stunk when lined up in true 4-3, it stunk a whole lot less when in a 3-4 and Mack at LB. Zoinks!