You might have made a post on this but is there any evidence to suggest having multiple looks (4-3 + 3-4) actually leads to better defense? Maybe more sacks, turnovers?
Belichick has been doing it the past 2 years (maybe more but I've reviewed the Pats past 2 seasons in detail).
- In 2018 the Pats were a base 4-3 but that really just defines what alignment they were in most often on 1st downs and short yardage situations.
- In 2019 the Pats were a base 3-4 but again that just defines what alignment they were in most often on 1st downs and short yardage situations.
For both Belichick and in the past for Mike Nolan the varied fronts are focused on methods to stop the run without a big sacrifice in pass defense.
- Marinelli's only significant variation was to use a 3 man DL on passing downs (i.e. a 4-3 with 1 DT removed).
- The Cowboys used the 3 man DL more in 2019 than in the past under Marinelli.
- Jaylon would play a hybrid LB/DL role with the 1 DT out and another LB would come in and play Jaylon's normal role.
Both Belichick and Nolan like to play the run with "7 men in the box" by using varied fronts.
- Instead of having the 8th man up, they use a bigger overall front 7 when they want to stop the run.
- You'll often see the Pats SS up but that's often with the Nickel CB back like a 2-deep Safety (i.e. Still 7 in the box).
The Pats defense has evolved to be centered around big LBs. They only had 1 LB that played significant snaps in 2018 and 2019 that was under 250.
- In 2019 they only had 2 DL over 300 pounds.
- It will be interesting to see their performance this year because the on-field "brains" of that defense was hybrid LB Kyle Van Noy and he departed in free agency.
- They drafted a DE in 2019 (Chase Winovich 6-3, 250) that appears to be the replacement for Van Noy.
- Winovich is listed on the Pats roster as a DE but he played primarily as a LB in 2019.
Both Belichick and Mike Nolan like to play 2-deep Safety alignments (often Quarters coverage).
- A huge problem for the Cowboys in 2019 was that they would align the single high FS towards the side with 2 WRs (i.e. the side with the slot WR).
- That meant no deep help on the other side.
- In Quarters coverage there is a Safety on both sides instead of 1 deep Safety trying to cover the entire width of the field.
- Quarters improves intermediate and deep pass defense but is a 7 man in the box type alignment vs the run.
- By using a bigger front 7, run defense is improved without an SS up in the box.
- Obviously bigger hybrid DE/LBs are not a good in pass coverage as most 4-3 LBs but that is offset by having both Safeties back in a better coverage alignment.
- An added benefit of a using Quarters as the base coverage is with regards to roster management.
- Both Safeties are similar without the need to carry 2 separate types of Starters and Backups.
- The 3rd best Safety can easily backup both spots; whereas, with single-high schemes the backup SS might be different than the backup FS.
In 2019 with Kris Richard responsible the back 7 and calling the plays but not having control over the DL, his only recourse to improve in stopping the run was to sacrifice pass defense.
- KR basically just took away both deep inside and short inside help from the CB on the side with 1 WR. That was most often Awuzie.
- At the same time Awuzie still had significant responsibilities in run defense while having no help in pass defense.
- Even Deion and Richard Sherman didn't have that much responsibility to be superman.
- Deion had no help in pass defense but didn't have extensive expectations to come up and stop outside runs.
- Richard Sherman had either deep inside help from Earl Thomas or short inside help from LBs and the SS. He often had help both short/long inside.
Many defenses use an SS in the box to improve run defense or keep the SS back for the best pass defense.
- In the past couple of years the Cowboys would often have SS Heath up in the box area but he still had responsibility to play man coverage from short to deep.
- We saw in 2019 when Heath missed games that Thompson couldn't play that style because he didn't have the elite speed of Heath.