There are numerous factors weighing down the Jets defense right now. You can’t say the struggles are due to any single factor.
To me the most frustrating problem is the inability to execute basic concepts.
On this play in the first half the Jets are in quarters coverage. This type of coverage has both outside cornerbacks and both safeties responsible for one-fourth of the deep part of the field. This coverage is designed to wall off downfield passes and force a checkdown. One of the players responsible is Isaiah Dunn who is starred.
However, as the play develops Dunn is occupied with an underneath receiver, and this leads him to vacate his assigned space. Another receiver sneaks behind him.
Miami is able to hit an easy pass for a nice gain.
Here the Jets are in their base Cover 3 coverage. The two outside cornerbacks (including the starred Dunn) and one safety split the deep part of the field into thirds. There are four defenders responsible for underneath zone.
Again Dunn gets distracted and allows a receiver to slip behind him into his assigned area.
It’s another big gain. The Jets get bailed out here because of an unrelated penalty.
On this last play Michael Carter is blitzing from the slot along with the four defensive linemen.
Based on the way the play proceeds it is difficult to see exactly what the defensive playcall is. It could be man to man with one deep safety.
It could also be a fire zone with three underneath defenders and three defenders responsible for the deep part of the field.
Mack Hollins in the slot is matched up against Jets safety Elijah Riley.
Riley releases him as though he’s expecting deep help. If this is man to man, he was wrong. If it was a fire zone it would be the outside corner who needed to drop (once again Dunn being distracted). Hollins breaks wide open.
Before you destroy Dunn I will say that my personal guess is this was supposed to be man to man coverage. I am basing that on how the linebackers react to the running back and tight end who stay in to block. The linebacker are eying these players at the snap, indicating they would take them in man coverage if they released into routes. If it was zone coverage, I would expect them to just make zone drops. I can’t say this with 100% certainty, though.
What I can say with certainty is this busted coverage turns into a touchdown.
There are some instances where I won’t blame a player for failing to execute. A week ago when Stefon Diggs repeatedly beat Brandin Echols and Javelin Guidry, I couldn’t get on the Jets corners. They were put into mismatches and couldn’t possibly be expected to hold up.
You also will see occasions where a coaching staff calls coverages that are a bit too complex for young players to understand. Again I can’t blame the players for this.
This is a case where Jets players repeatedly are failing to execute basic concepts. These are base defensive calls that are in any NFL playbook. You have to know where to be. I really don’t mean to pick on Dunn here. I will say that every time I have seen him on the field, including in preseason, he has looked totally lost. The Jets gave him record money for an undrafted free agent, and I have yet to understand what they see in him.
This is part of a bigger story, though. The problems transcend one player. My guess is the last one isn’t on Dunn’s fault, and these consistent breakdowns have been happening long before he entered the lineup. Every game you have big plays that result from defenders not knowing where they need to be. These aren’t rookie mistakes. To be in the NFL, you have to be able to do the simple stuff.
If the Jets defense can't learn to execute on this basic of a level, there isn’t much hope for them. There are no easy fixes to turn this unit from a weakness into a strength. There is clearly a talent deficit, but right now the players aren’t even controlling the things they should be easily able to control.