49ers depth chart: Linebacker is thin behind Fred Warner, Dre Greenlaw

The 49ers aren’t necessarily weak at linebacker, but they better hope Fred Warner and Dre Greenlaw both stay healthy in 2021.

The San Francisco 49ers have arguably the best linebacker in the NFL right now, 2020 All-Pro Fred Warner. Right behind him on the depth chart is third-year pro Dre Greenlaw, who despite some up-and-down moments last season, is a quality starting-caliber option.

After that, though, the Niners depth chart is a bit shaky and somewhat worrisome.

Fortunately, both Warner and Greenlaw have enjoyed a relatively clean slate of health since pairing together for the first time back in 2019 — Warner, yet to miss a game over his three-year career, and Greenlaw having missed only three.

Hopefully, that remains the case again. But entering 2021, it was pretty clear general manager John Lynch and head coach Kyle Shanahan weren’t entirely satisfied with the team’s positional depth here.

Hence why San Francisco signed undrafted rookies Justin Hilliard out of Ohio State and Elijah Sullivan out of Kansas State.

Another move, the fifth-round addition of USC safety Talanoa Hufanga, could potentially alleviate some of the depth shortages at linebacker, too. Hufanga, a playmaker last year and someone who can act as an in-the-box pass-rusher, has linebacker-type tendencies and could end up being one of those prototypical safety/linebacker hybrids so prevalent in today’s NFL.

Yet all three of these first-year players are rookies, and it’s impossible to say one way or another they’ll pan out within the pro ranks.

This might partially explain why the 49ers flirted with former Denver Broncos veteran linebacker Brandon Marshall last week, as ESPN’s Adam Schefter reported:

Marshall, who’ll turn 32 years old this September, hasn’t played since 2018. If anything, he would have been a mere depth option with some experience.

Same with journeyman backup linebacker James Burgess, whom the Niners eventually signed to a one-year deal.

More pressure on 49ers reserve LB Azeez Al-Shaair?

Even if both Warner and Greenlaw remain fully healthy and see plenty of action this season, there will be the need to spell them from time to time while also guarding against injury.

For the latter half of last year, this was the primary responsibility of now third-year pro Azeez Al-Shaair, who looked every part of a rookie back in 2019 when asked to take defensive snaps but showed some modest improvement in limited action last season.

In terms of statistical numbers, Al-Shaair went from 18 tackles in 2019 to 35 tackles in 2020, also improving his Pro Football Focus grade from a lowly 42.1 to a respectable 61.0 last year.

That said, Al-Shaair still lacks in the pass-coverage department, giving up a 99.0 passer rating when targeted while also surrendering 201 yards after the catch.

Related Story: 49ers better extend Fred Warner sooner than later

This might be another key reason why the Niners wanted to infuse some competition for Al-Shaair this season. Hufanga, in particular, looked far better in pass coverage at the college level despite his lack of straight-line speed, suggesting he could bump Al-Shaair back down to a strict special teams role.

Ideally, however, both Warner and Greenlaw won’t need to be relieved too much. The goal is for both of them to continue their reputations of being both healthy and reliable.

But if either goes down with a lengthy injury, San Francisco could be scrambling to find an adequate option buried deep on the depth chart.