Jumping Down the Rabbit Hole of Chiefs New 43 Defense

by Laddie Morse | May 10, 2019

It’s been a decade or so since the Kansas City Chiefs last used a 43 Defense that new Defensive Coordinator Steve Spagnuolo will be instituting this season. When head coach Andy Reid decided he would move on from Bob Sutton and chose to bring in Spagnuolo, he also accepted the idea that the 43 would be making the trip too. So, it’s time for jumping down the rabbit hole of the Chiefs new 43 defense.

Prior to the time Andy Reid came to Kansas City in 2013, his team in Philadelphia ran the 43 defense. When asked at that time if he’d stick with the 34 that was already in place here, Reid offered:

“The 4-3 is good if you have the right coaches in place and the team is invested in it. But this team here is invested in the 3-4, so let’s continue to build it and get better at it.”

It was a year or two after Tamba Hali was drafted by K.C. with the 20th pick in the 2006 NFL draft that the team made the conversion away from the 43 and to the 34, which K.C. has been running until now. Back then, the chalk talk and scuttlebut was all about whether or not Tamba could make the switch to the 34, which he did well enough to reach 2nd place on the Chiefs all-time sack list (89.5 sacks) behind only Derrick Thomas, where Hali remains to this day.

The “Base” Identification

First of all, fans need do know that the 43 only refers to the base defensive-set that the Chiefs will use. From listening to Steve Spagnuolo, Brett Veach, and Andy Reid talk about the players they have brought in to furnish the their new scheme, all those players offer a component of versatility. That’s going to be an important and key element of the “new” Spagnuolo defense. You’ll hear me refer to that element several times here.

A Base Can Be a Misnomer

While we may be talking about the “43” vs the “34” in certain segments of this piece, it can actually be a misleading ID. Here’s what Football Outsiders had to say, in a piece written by Bryan Knowles, about the different sets teams line up in. This is based upon research they did in the 2016 and 2017 seasons so it should apply here for the most part.

“In all honesty, the distinction is becoming more and more meaningless in the modern NFL; the difference between a 4-3 defensive end and a 3-4 outside linebacker is more or less whether or not they have their hand in the dirt at the snap. Hybrid defensive schemes are the name of the game now….”

Football Outsiders also offered the following chart which clearly illustrates the percentage of snaps dedicated to the different scheme that Defensive coordinators use throughout the season:

Let’s define some terms here:

• Base Defense– 34 or 43 defense, by name.
• Nickel Defense– a defensive set that uses 5 defensive backs, and the 5th is called the nickelback.
• Dime Defense– a defensive set that uses 6 defensive backs.
• Goal Line Defense– a defensive alignment near the goal line, with fewer than 4 DBs.
• Big Defense– are 4-4-3 or 3-5-3 set-ups.
• DVOA (Defense-adjusted Value Over Average) calculates a team’s success based on the down-and-distance of each play during the season, then calculates how much more or less successful each team is compared to the league average (from Football Outsiders).

So why even have this conversation if the DCs of the league are having their base players standing on the sidelines so often? Well, there’s the personnel side of this and then there’s also what works, or, is successful. Football Outsiders also said:

“… 55 percent of base snaps were 4-3 defenses, and 44 percent of them were 3-4 fronts. That doesn’t add up to 100 because there were a handful of 2-5s, 5-2s, and 1-6s that popped up here and there. Carolina was the only defense to never stray from their front; they were a 4-3 defense and only went to a three-man line on 26 snaps all season long, all of them in nickel defenses. At the other extreme was New England, who freely flipped between 3-4 and 4-3 defenses when they could be bothered to be in base defense at all….”

What jumps out here is the mention of a defense like the Panthers who stay almost exclusively in their base alignment. However, if you consider that they had LBs like Thomas Davis and Luke Kuechly who were manhandling the middle then you can understand why they might have been able to do that. On the other side of this quote you’ll notice reference to New England. Now, who do you think was the Defensive line coach for the Pats in 2016 and 2017? That’s right, the Chiefs current D-line coach, Brendan Daly.

As I mentioned before, you can expect that these coaches and this collection of players will be mixing and matching defenses more than Andy Reid has plays in his playbook. Well, maybe not that much, but you get the idea.

So, let’s take a look at how the basic 43 base looks on the drawing board:

For those of you just joining us, the “4” in the 43 alignment refers to the 4-man front… while the “3” in the 43 scheme is talking about 3 Linebackers. Next, we’ll take a reverse angle look at how this appears on the field.

Not shown here are the Cornerbacks but this clearly displays the front four down linemen, DL with their hand in the dirt, and three standup LBs. So, let’s define the roles of these Linebackers.

• SAM– the strong-side linebacker (SLB) will line up across from the side of the offense—starting at the center—which has the most players on that side. If the number is equal, we count men on the line of scrimmage. Usually, the SLB will line up across from the TE (if each side has the same number of personnel).
• WILL– the weak-side linebacker (WLB) will line up across from the side of the offense—starting at the center—which has the fewest players on that side.
• MIKE– the middle linebacker (MLB) goes in the middle, nearly straight downfield from the offensive Center.

Here’s one more angle of a team, the Chicago Bears, lined up in the 43. What’s of note here is that the Bears usually run a 34 base. So, you can see that teams use varying approaches dependent on the situation and personnel they’re dealing with on offense as well as down and distance.

As you can see, Khalil Mack has been designated and in the Chiefs 43 that player would be Frank Clark. The player just off of Mack’s left shoulder is either a LB or CB or Safety and if it’s not a Linebacker then this set-up is a 4-2-5. Meaning, the Bears would be employing 5 DBs on this play.

Why All the 43/34 Talk At All?

When an offensive Center approaches the line of scrimmage he usually has to make 3 calls:

1.  Identify the defensive front,
2.  Identify the Mike LB and,
3.  Give the box count (the # of players in the box)

Now, if a DC can call a defensive set which changes the responsibilities of his D-line and LBs and thereby confuse the Center, then he can make the blocking assignments almost impossible to determine for each OL. Once that happens, the defense has won half the battle.

From an offensive perspective, this is one reason I continue to be a big Andy Reid supporter because he uses so much pre-snap motion in his playcalling that the Center and the QB are able to read the defensive alignments and then running a play becomes a lot easier if  you can determine where everyone will be once the ball is snapped.

From a defensive Coordinator’s point of view, if he’s able to bring in players who are versatile and can play a variety of roles within the defense, then it becomes a chess game that other teams will never be able to keep up with. I strongly believe the #1 reason the Pats beat the Chiefs in Arrowhead this past January is, the unpredictability of their defense. Yes, yes, I know that the Chiefs took them to overtime but you also must recall that Patrick Mahomes didn’t score until the second half. The Patriots held the Chiefs Mr. Wonderful to zero points in the first two quarters of that game. During the regular season, there were only 3 times that the Chiefs could not score in a quarter (of any given game) and that happened only 3 time in 3 seperate games and yet, the Pats held the Chiefs high powered offense to zero points in the first two quarters of their playoff game. At Arrowhead no less.

The good news is, the defensive line coach for that Patriots team is now the DL coach for the Chiefs and every trick in the book that he helped the Pats use on PMII and crew, he’ll now be employing vs. the rest of the league and most importantly, when the playoffs roll around again.

The Difference Between the 43 and the 34

So, what is really the biggest difference in running the 43 defense? It most likely comes down to personnel. When you have a NT who can dominate like Dontari Poe (before he had back problems), then attacking up the middle is more of an option and everything else works from the middle out in the defensive scheme of things. Poe was able to slide sideways vs the run and eat up two blockers in the process and the Offensive coordinators he would face needed to send two men in to account for him thereby changing the blocking assignments on offense… and that would then free up the linebackers to attack the ball carrier more freely (which, Derrick Johnson was great at in all his time behind Poe).

Nose tackles like Dontari Poe don’t come around everyday and when the Chiefs got their hands on him, they wore him out. It raises the question about who could play that NT role when the Chiefs use the 34 which they will do at times because, as we’ve already established, they won’t be in their base a 100% of the time (and no team is). Derrick Nnadi made a lot of headway last year as a rookie and he fits the NT role as well as a DT role. Nnadi would sometimes deserve double-teaming which is basic to the 34 but now he has help in Khalen Saunders. Xavier Williams could play this role but will likely get limited snaps as the season progresses, if he makes the 53 man team.

Difference Making Linebackers

The primary rushers in a 43 are the defensive ends but in a 34, the primary edge rushers are the OLBs. That meant that the 34 was using two players “called” linebackers to do the rushing of the QB. So, in essence, you had 5 guys up on the line of scrimmage. Now, in the 43, there will be four DL with the two DEs getting after the QB (and setting the edge vs the running game as well) and the 3 Linebackers will be used to stop the run and focus more completely on the run. That will allow them to be more aggressive.

I played Linebacker in my younger days and know that the first step is everything to stopping a play. If your DC is asking you to hold back and slide along the line of scrimmage (as I believe Bob Sutton was asking the 2018 LBs to do) then they’d have to wait to make a play and consequently, blockers coming off the line of scrimmage had time to get into their body. If the first step for a LB is towards the ball based upon the movement of the running back or the QB (if it’s a passing play), then a LB knows immediately if he’s going in coverage, blitzing (because of a pre-snaps call) or to the hole to stop the run (in which case he can often beat the blocker to the point of attack). Sutton had his LBs waiting to make up their minds where the play was going and using them more like a Safety, a last line of defense.

While my read on the Chiefs linebackers was poor play by Anthony Hitchens (and others) throughout 2018, this season will tell us everything we need to know about whether that was due to Bob Sutton or not. With only one addition to the Linebacking corp in Damien Wilson, this crew is almost exactly the same group. Sometimes, a group needs time together to “figure it out” so I’m hoping that will help this crew too.

Lovie Smith has talked about the advantages of the 43 and says this :

“You do not have to teach your linemen to drop and defend the pass. All your time in practice is spent teaching them to attack and defeat the pass protectors… the advantages of [the 43 is] keeping the assignments simple… it makes the time in practice much more effective.” 

While I’m sure Steve Spagnuolo wants to keep it simple in the beginning, I also expect him to “complexify the crap out of it” to keep opposing OCs off balance… and winning that chess match has become what it’s all about.

Laddie Morse — ArrowheadOne

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