49ers 2017 Season: San Francisco’s new run defense

The players

The first thing anyone discussing how the 49ers have addressed the run defense is recognizing what they accomplished in the first round of the 2017 NFL Draft.

Arguably the two best run defenders in the draft were acquired, two blue chip prospects that figured on many teams draft boards to be in the top five overall.

Stanford DE/DL Solomon Thomas and Alabama ILB Reuben Foster were two of the top three prospects on the 49ers draft board. And not only did they get them both, but it shows the priorities San Francisco had in addressing this run defense.

After losing stalwart ILB, and fan favorite, NaVorro Bowman to injury at the beginning of the season last year to an Achilles tendon tear, the team’s run defense could not keep up with even the most mediocre of opponents.

When you closely look at the new scheme on the strong side and weak side you can piece together the thinking of the new regime. We will throw up the front seven graphic again here for reference during the breakdown:

Let us before we go further, address the “Elephant” in the room, or as many would say these days the LEO. It is the much discussed and criticized position that the legendary 49ers defensive coach George Seifert first introduced to the NFL and this 4-3 under scheme.

Now I know that you might say that we talked about this in part three to a degree but the relevance to exactly what the new regime could be planning is paramount to the run defense as well.

The Elephant position was widely considered the largest position of need with the advent to the new 4-3 under scheme because of the lack of a true hybrid pass-rusher on the 49ers’ roster coming into the 2017 season.

After Myles Garrett, who went No. 1 overall, there was not a true pure pass-rusher who fit the mold that could be justified with a top-five selection. This did not faze the 49ers in the slightest bit and, as a matter of fact, their intentions and future plans along the defensive line played out exactly as they intended.

San Francisco selected Solomon Thomas with the third pick overall after creating enough uncertainty and trading back one spot, all the while getting the very player that they wanted all along.

The projection of what the 49ers are thinking starts here.

Thomas was considered to be a “tweener.” What this means is that his measurables placed him at several different positions on the defensive front.

In reality, Thomas can and has played everywhere along the D-line with much success. He was rated at the top of all categories involving run stopping and quarterback pressure from an interior lineman and proved to show the versatility to be placed situationally anywhere along the line of scrimmage.

The 49ers shocked the public with the announcement that they were working their 2015 first-round draft pick, Arik Armstead, at the elephant position not long ago. Armstead, who measures in at 6-foot-7 and 290 pounds, does not fit the popular traits of the modern day LEO. He is traditionally a 3-4 DE that plays a hybrid run-stopping and pass-pressuring force from the inside.

The modern day LEO plays much smaller and faster. When Seifert first introduced this concept in the early 1980s he was using the average-sized defensive end to be this dedicated pass-rusher, and while he chose the fastest prospects, the Elephant was born.

As stated in part three of this series, Julias Peppers, who is virtually identical in size to Armstead has been playing in this regard with much success for the past couple of years with the Green Bay Packers.

Armstead is the modern day DE, Thomas is the modern day “tweener” and 2016 first-round selection, DeForest Buckner, is a physical clone of Armstead with possibly more ability. Why this is all relevant to the run defense will be made evident in a moment.

Outside of the Elephant position, the remaining defensive linemen are the weak side DT, the strong side DT or nose guard and the strong side DE.

Weak side defensive tackle and strong side defensive end

With the selection of Thomas and the up and comer Buckner both now on the team, the majority of the opinions out there have Buckner at this position and Thomas as the strong side DE.

I am going to go ahead and call this the opposite, and I will explain why. In the 4-3 under, you typically want your best interior pass-rusher at the weak side DT position and your best run-stopping DE on the strong side.

In college, Thomas proved to be the best pass-rusher coming from the interior defensive line in the nation. Last year, Buckner was San Francisco’s best run-stopping DE, and both at the same time show great ability to do either or.

What this all boils down to is if the 49ers have Armstead and Buckner at both DE positions, they are properly trained to both play the Elephant pass rush and stuff the run on either side, Thomas can rotate anywhere situationally, then any tight end in motion changes nothing on the D-line and becomes only a shift with the SAM LB and weak side safety.

The easy gap assignments and pass pressure take away many of the opposing offense’s audibles and motion adjustments without giving away the defensive play or having to shift at the line of scrimmage.

This could prove to be a huge asset. Even if Thomas and Buckner switched, the same could apply with Thomas’s versatility. The rest of the positions that make up the run defense are a bit more defined but still have the versatility aspect play into this possible conundrum for offenses.