Breaking down 49ers defensive tweaks and changes in 2019

With the San Francisco 49ers being off from training camp today, Niner Noise explores some of the minute differences the defense will employ in 2019.

The San Francisco 49ers have a day off from training camp today, meaning there’s a little time to reflect on other things aside from who’s impressing during practices and whatnot.

One of the hot topics during the offseason was how the Niners are switching to a wide-9 alignment — a subtle, yet important defense where the strong-side EDGE lines up outside the right shoulder of the inline tight end.

In turn, this will force the strong-side (SAM) linebacker off the line of scrimmage into a more traditional “stack” role, which also pushes the strong safety back deeper in the secondary.

As a result, the two safeties become much more interchangeable, which is something defensive coordinator Robert Saleh pointed out to The Athletic’s Matt Barrows (h/t Kyle Posey of Niners Nation):

"We tried to marry base (defense) to nickel more. …We feel like we’ve been able to marry the two together so there isn’t as much of a tendency. So to the players we might look more interchangeable, but we’re actually no different than what we do in nickel."

Speaking of nickel defenses, that’s going to be the prime formation San Francisco winds up using this season. Base personnel (four defensive linemen, three linebackers and four defensive backs) isn’t exactly a base defense any longer. Last year, according to Football Outsiders, defenses used base formations just 25 percent of the time. Nickel formations, which remove a linebacker and add a defensive back (typically a nickel corner, hence the name), were used 60.5 percent of the time.

The 49ers were close in line with this trend, featuring base defenses 26 percent of the time and using nickel 72 percent of snaps. San Francisco hardly used dime formations (six defensive backs), going there just two percent of the time in 2018.

So, while there are some alignment tweaks, the personnel certainly isn’t going to change much. And this partially explains why the Niners might be perfectly comfortable giving rookie linebacker Dre Greenlaw first-team reps at SAM in training camp, since that’s the linebacker regularly coming out in nickel.

As Posey pointed out, backup defensive linemen — Jullian Taylor or Kentavius Street — are probably going to get more snaps in 2019 than nose tackle D.J. Jones, who figures to be on the field only a quarter of all defensive snaps.

And similarly, nickel corner K’Waun Williams will likely see the field more than Greenlaw, too, as long as the Niners continue last year’s trend.

“If you really go look at our season last year, we played 200-300 snaps of base defense,” Saleh continued. “And in those snaps, I think we had like 50 snaps with the offense in two-(running) back all year. We did not see a lot of two-back. Everything is “11” personnel (three wide receivers) looks, spreading you out. They’re just not letting us get into those (base) formations anymore.”

Going off this, as well as the aforementioned percentages, all one needs to do is realize the nickel formation is going to be how the Niners deploy themselves, defensively, for the majority of 2019.

Heck, most of the league is going to as well.