Why Arik Armstead Believes the 49ers Defense Can Improve in 2020

Arik Armstead used to let DeForest Buckner do most of the talking for him in the 49ers locker room.

Arik Armstead used to let DeForest Buckner do most of the talking for him in the 49ers locker room.

But now Buckner is a Colt, and Armstead has become one of the highest-paid players on the 49ers, so he must become a leader as well. And he’s beginning to find his voice.

When asked how the 49ers defense can improve after a dominant 2019 season, Armstead was specific.

“One thing we talked about,” he said, “we were tops in a lot of categories except run defense, where we were middle of the pack. Definitely looking to get better in that aspect.”

Calling the run defense “middle of the pack” is generous. The 49ers gave up 4.5 yards per carry, which ranked 10th worst in the NFL.

So what has changed since then?

The implication is the switch from Buckner to Javon Kinlaw at defensive tackle will help the run defense. I don’t know if Armstead meant to imply that. But if he did, he’s probably correct.

Buckner is a great player, but he was the weak link on the defensive line last season in terms of run defense. And that’s not to say he’s a bad run defender -- he’s a good one. In 2017 and 2018, the 49ers run defense ranked 7th best each season in yards per carry allowed, and Buckner played on those teams.

But in 2019, the 49ers changed their defensive scheme. Started using the “Wide 9”, which is inherently weak against runs up the middle, because the defensive ends line up extra wide to supercharge the pass rush. Meaning every offensive line is free to double-team both 49ers defensive tackles and push them down the field like ice blocks.

Buckner isn’t built to hold his ground against double teams -- he’s tall and lean and built to beat one-on-one matchups. Same for Armstead, which is why the 49ers play him at defensive end instead of defensive tackle in their base Wide 9 defense.

Kinlaw can withstand double teams. He’s 25 pounds heavier and three inches lower to the ground than Buckner. Kinlaw even played nose tackle at times during college. He’s a boulder. Which means he’s a perfect fit in the Wide 9.

That doesn’t mean Kinlaw is a better player than Buckner. But on this particular 49ers team, the way it’s currently constructed, Kinlaw should improve the run defense.

I think that’s what Armstead was trying to say.