49ers run defense overcame struggles to cement elite status despite missing Arik Armstead and Javon Kinlaw

When Arik Armstead went down for the 49ers in Week 4 against the Los Angeles Rams after Javon Kinlaw sustained an injury in Week 3, San Francisco immediately had depth concerns alongside the interior of their defensive line, which had been the bread and butter of their run defense over the past few seasons.

Memories from the 2021 season came to fruition, as the 49ers struggled in the running game without Armstead when he wasn't primarily an interior defensive lineman over the first eight games.

During that stretch, the 49ers allowed over 100 yards rushing in seven of their first eight games, beginning the year 3-5 and at risk of missing the playoffs.

When Armstead was moved to primarily be an interior defensive lineman, the 49ers allowed 100 yards rushing to an opponent just once, which came due to a 73-yard rushing touchdown from Travis Homer in Week 13 on a fake punt.

Fast-forward to the 2022 season and the 49ers faced a similar predicament as Armstead was not to practice for eight consecutive weeks, while Kinlaw was placed on Injured Reserve and hasn't returned since.

The Wake-Up Call

After a strong response from the defense in a 37-15 Week 5 victory over the Carolina Panthers, the 49ers were dealt with a tough hand: they were to face the best opposing offensive line and rushing attack thus far, while missing Nick Bosa alongside Armstead and Kinlaw.

The results were porous as the Falcons ran for 168 yards on 40 attempts, dominating the line of scrimmage en route to a 28-14 victory over the 49ers.

Bosa returned the following week, but a heavily injured 49ers squad struggled once again against a Chiefs offense known for their ability to stretch the field, allowing 112 yards on the ground on only 21 attempts in a blowout 44-23 loss.

In both losses, tackling was a primary issue, as well as setting the edge, which allowed opposing offenses with strong offensive lines to impose their will to dominate the trenches.

The return to "elite" status

At 3-4 with the division in peril due to a surging Seattle Seahawks team, the 49ers needed a change, which started with their strong suit: defense, and specifically run defense.

During the time, it was clear that both Arik Armstead and Javon Kinlaw were in no shape to return imminently, meaning the current makeup of interior defensive linemen was going to need to step up and make plays in order to return the run defense to the performance it sustained during the beginning of the season.

Kevin Givens, who was a standout during training camp, was a figurehead of San Francisco's transition, as he and Hassan Ridgeway began earning starts on the interior following the injuries.

In a way, Week 8 was similar to San Francisco's dominant performance last year in Week 10, when the 49ers were 3-5 and on the verge of a failed season.

The 49ers got their run defense clicking, allowing just 56 yards on 2.7 yards per carry, which effectively limited the Rams' offense, especially in the second half where they were blanked out in a 31-14 rout.

The dominance only began there as the 49ers allowed 51, 67, and 63 yards on the ground in subsequent weeks following the bye week, despite facing the likes of Austin Ekeler in Week 10 and Alvin Kamara in Week 12, allowing just 2.9 yards per carry in those matchups.

During that four game stretch, the 49ers have miraculously failed to allow a single second-half point, which included a shutout over the New Orleans Saints last weekend.

Is the 49ers defense better than their early season marks?

The resurgence of the 49ers' rushing defense has cemented themselves as the top team in yards allowed against the run, giving up just 79.5 yards per game on the ground over the season.

However, over the past three games, the 49ers have done even better than their regular season mark, allowing just 60.3 yards per game on the ground.

Not only have the 49ers' limited the volume of opposing teams in their rushing attacks, but also the efficiency in how they rush.

On the season, the 49ers have allowed just 3.3 yards per carry, which is, by far, the best mark in the NFL. But, over the past three games, that number has decreased to just 2.9 yards per carry, signifying how dominant the defensive line has been against the run, despite missing Arik Armstead and Javon Kinlaw.

The numbers don't span to just the run defense, however, as the 49ers have allowed the least yards per game(281.7) to opposing offense by a wide margin.

Similarly to the run defense statistics, San Francisco has shored up in recent weeks, allowing less than their league-leading season mark, giving up just 270 yards per game over their past three outings.

Overall, the efficiency has been there as well as the 49ers have allowed just 4.7 yards per play, best in the NFL, which decreases to 4.5 yards per play when extrapolating just the last three games.

That leads to the question? Has the current 49ers defense performed better than their early season marks?

The answer is much more complicated than a yes and no.

But, it was expected that the defense would take a step back, especially in run defense, without the likes of Arik Armstead and Javon Kinlaw, hence the outcry to trade for a defensive lineman at the deadline.

However, Kevin Givens, Hassan Ridgeway, and the plethora of interior defensive linemen that the 49ers have utilized have sustained success, which has been a significant reason why the 49ers have been able to go on a four-game winning streak.

While the winning streak could come to a halt this weekend, the run defense should only improve when the 49ers return Armstead this weekend, who has been their best defender against the run when he's been healthy over the past few seasons.