The final score in the Steelers' 30-9 loss to the Jaguars doesn't tell the whole story of the game. Normally that would lead one to think the defense was completely destroyed, but only allowing two touchdowns while your offense commits five turnovers tells a not-so-simple tale.
We go to the film room to show where the defense had its breakdowns and where it was able to keep the Steelers in the game until late in the fourth quarter ...
Leonard Fournette ran the ball 28 times for 181 yards, and half of that came on his final carry of the game. The Jaguars' offense came into the game with the NFL's No. 2 ranked rushing offense, yet coming into the fourth quarter Fournette only had 41 yards on 14 carries for an average of less than three yards per carry.
Looking at the the defensive letdowns in the fourth quarter, the proper evaluation of the unit's performance considers whether they were systemic problems or individual gaffes.
A systemic problem is more difficult to solve and worrisome for the unit as a whole moving forward. Individual mistakes are more correctible and take some film room sessions to learn why they happened, and how to avoid similar problems in the future.
Looking at where the Steelers' run defense failed on film points more to the issues being individual mistakes late in the game rather than major schematic issues. That became noticeable as the defense had to keep trotting back onto the field, with Jaguars quarterback Blake Bortles feeling no pressure to carry his team.
The pregame thought was that Bortles would have to beat them. Instead, the Jaguars were able to pound the ball late in the game and look for mistakes to open holes in the Steelers' defensive front.
Fournette's fourth quarter not only added 140 yards to his stats, but also doubled his carry total from 14 to 28. Prior to the fourth quarter, Fournette only had one run more than 10 yards and was practically a non-factor outside of his 2-yard touchdown dive.
He became a factor when the Jaguars kept getting the ball back with a lead after the Steelers' offense punted once and threw two interceptions for Jacksonville touchdowns. That kept putting the defense back on the field with no pressure on the Jaguars' offense to get aggressive and take risks that could lead to turnover opportunities for the Steelers' defense.
One of those individual mistakes I referenced above came when Fournette bounced a run to the outside for 11 yards on a fourth-quarter field-goal drive.
The Steelers' defense came out in an inverted 3-4 defense with Bud Dupree lined up stacked over Stephon Tuitt. Fournette bounces his run to their side and neither of them maintain the edge.
Tuitt jumps to the inside gap, but so does Dupree, which means both are occupying the same gap. That means somebody made a mistake and the other was in the right, and my money is that Dupree was wrong. Watch how he focuses on the fullback and follows him right to the C-gap, giving up the edge:

I saw T.J. Watt dip inside on a similar situation later in the drive, but also saw both outside linebackers work well out of the same formation earlier in the game. So it seems as if in that situation, each linebacker was trying more to account for an extra gap and leaving his responsibilities late in the game when trying to make a play.
Also worthy of note on this play was how Fournette openly called out Mike Mitchell only to get taken down hard. Mitchell got up and celebrated his big hit in a manner that gave me the impression he was trying to ignite some fire into the flat-footed Steelers.
While Fournette did gain a first down on the play, Mitchell filled his responsibility of coming up to help after the front gave up the edge.
I asked Watt about responsibilities when the Steelers show that kind of alignment in their front and he didn't specify those particular runs, because the defense prides itself on having various assignments with each formation in order to keep offenses guessing:
While the defense did give up over 200 total rushing yards, they did execute the plan to shut down Bortles as they held him to 95 yards through the air, no touchdowns, two sacks and an interception.
Watt got one of those sacks and simplified their plan to bring heat on Bortles when I talked to him after the game.
"We knew he wanted to scramble when the passing lanes weren't open," Watt said of Bortles. "So it was key when you were at the top of the rush lanes to spin back somehow so that you couldn't let him scramble out."
That doesn't sound at all like a player who was unsure of his gap responsibilities. And the closer I look at the film, the more I see it was less about confusion and preparation, and more about simple mental mistakes and individuals who failed to stick to their responsibilities when trying to make a big play.
The defense avoided those kinds of mistakes for most of the game, but the fourth quarter saw just a few mental gaffes that led to big-play opportunities for the Jaguars.
The mistake that led to the Jaguars' biggest play of the day put the game out of reach for good when Fournette ran for a 90-yard touchdown.
The Jaguars call for a trap run to the weak side of the defense. The Steelers have five defenders lined up to the left of the center while the Jaguars only show four potential blockers in their guard, tackle, tight end and fullback.
The trap in this play is that the offensive line crashes the defensive line to the inside while the fullback kicks out Artie Burns on the outside and Mitchell is allowed to come free through the line. Mitchell is left untouched so the Jaguars can pull their right guard and 'trap' him, effectively matching their five blockers to the Steelers' five defenders on that side of the formation:

The primary way to stop this is for a Steelers' inside linebacker to recognize the pulling guard and follow him to the play. Typically when a guard pulls, they are pulling to go block at the point of attack. Vince Williams is the linebacker over that guard, but he never even sees the guard leave his spot and nobody can help the overmatched weak side of the defense.
These are the small mental mistakes that can lead to big problems, but it took a while for the defense to get to that point. I asked the defensive captain, Cam Heyward, about what the defense prepared to see in the Jaguars offense coming into the game in order to understand what their plan was:
"We prepared to stop the run," Heyward immediately stated. "But that's an 11-man job. When we don't execute fully, and we don't stay in our gaps or tackle properly, that's what happens and you give up runs."
Despite the defense allowing only one touchdown drive going into the fourth quarter, Heyward was adamant that they still needed to do more to help the team fight its way out of its problems, regardless of the five turnovers committed by the Steelers' offense.
"Their main goal was to run the ball and they were going to rely on their defense," he said. "As a defense we have to get off the field faster so that we can give our offense more tries."
The Steelers' defense didn't leave much room to improve considering that of the Jaguars' eight drives, four ended in punts and another ended in an interception. The defense gave up one long touchdown drive, a field goal and the long run by Fournette at the end of the game.
That lone interception changed the momentum of the game just before the end of the first half and took the Steelers from being down 7-3 with the Jaguars having the chance to extend the lead, to the Steelers kicking a second field goal and entering the second half down by a single point.
The culprit responsible for that turnaround was none other than the Steelers' defensive X-factor Ryan Shazier. Shazier continued to fly to the ball as he had all game long. He went in against Jaguars tight end James O'Shaugnessy and ripped the ball from his hands:

Every time I see Shazier going in for a tackle, he is also looking for any way to attack the ball. That makes for the third game this season in which Shazier has forced a turnover.
When I asked about how Shazier seems to always find himself around the ball, he focused on what he can do to be better for the defense.
"Honestly, I'm just trying to be the most productive player I can for our defense," Shazier said about his efforts Sunday. "My goal is to be one of the top linebackers in the league and at the end of the day, that's one of my goals, to get a turnover every game."
Shazier later stated that he feels like he is one of the best linebackers in the NFL, but that he still has a lot to prove.
As does this defense after a second game this season in which they surrendered over 200 yards on the ground. Regardless of how many times they are put on the field without the offense giving them a lead to protect, it's obvious that nobody is satisfied with minor victories here and there.
No matter how many stops or turnovers the defense forces throughout the game, they still know it's unacceptable to give up big plays on the ground at the end of the game, simply because they got worn down.
