What Is the 49ers’ Biggest Weakness on Defense?


Linebacker Patrick Willis. Linebacker Chris Borland. Cornerback Chris Culliver. Cornerback Perrish Cox. Defensive end Justin Smith.

Those are some of the notable standout players the 49ers defense lost after the 2014 season.

On the surface, one might view these losses as the crippling blow which finally ends San Francisco’s reign of boasting a top-10 defense since 2011.

Fortunately, general manager Trent Baalke has engineered a plan to build depth behind these losses in preparation for the time when each of these players would no longer be on the roster.

And it’s time to see whether or not Baalke’s plan will work.

San Francisco’s defense still figures to be a strength under head coach Jim Tomsula. The former defensive line coach boasted one of the best D-lines in the NFL prior to 2015, and that unit will remain a critical component heading into this season.

But will it be as strong as it was when Smith was at his peak?

Or will the middle linebacker position be a problem following the retirements of Borland and Willis? Maybe the cornerback position will be a liability. We don’t really know just yet.

The Defensive Line

December 20, 2014; Santa Clara, CA, USA; San Francisco 49ers defensive end Tank Carradine (95) during the second quarter against the San Diego Chargers at Levi’s Stadium. The Chargers defeated the 49ers 38-35. Mandatory Credit: Kyle Terada-USA TODAY Sports

Losing Smith hurts in a major way. The D-line anchor was the reason why former defensive coordinator Vic Fangio was able to rush no more than four players, which allowed the rest of his defense to drop back into coverage.

But even Smith had seen a decrease in playing time over recent seasons.

According to Jeff Deeney of Pro Football Focus, Smith appeared on just 66.7 percent of snaps last season. This was the lowest total of Smith’s seven-year tenure in San Francisco.

Under new defensive coordinator Eric Mangini, the 49ers will likely implement a rotational situation up front. Acquisitions of players like defensive tackle Darnell Dockett and rookie defensive end Arik Armstead will help solidify the depth here.

And healthy returns of D-linemen Glenn Dorsey and Ian Williams should only serve to bolster this group.

But the biggest name to watch should be that of third-year pro lineman Tank Carradine.

Known for his collegiate pass-rushing accolades, Carradine struggled to get onto the field last season until the final weeks. But he did flash some promise recording three sacks over the last three games of the year.

Next: Tank Carradine Is Key to 49ers Defense

Matt Maiocco of CSN Bay Area describes what Carradine’s projected role in 2015 may be:

"Now, the 49ers need to get production from a player who showed unique pass-rush skills as a senior at Florida State with 13 sacks. But as much as the 49ers would like Carradine to pile up sack numbers, it might be more important that he selflessly creates opportunities for outside linebacker Aldon Smith.Justin Smith played a huge role in Aldon Smith’s success as he routinely tied up blockers to allow the outside pass-rusher to come free on inside moves en route to the quarterback. Aldon Smith enters this season with 44 sacks in 50 career games."

The D-line’s success will likely hinge on which Carradine we see in 2015. Will it be the player who was inactive for all but one game prior to Week 11 last year? Or will Carradine look more like the physical force seen over his last three efforts?

Middle Linebacker

Jan 5, 2014; Green Bay, WI, USA; San Francisco 49ers linebacker NaVorro Bowman (53) during the 2013 NFC wild card playoff football game against the Green Bay Packers at Lambeau Field. San Francisco won 23-20. Mandatory Credit: Jeff Hanisch-USA TODAY Sports

Losing Willis and Borland hurts. There’s no way to get around that.

But, if there is any salvaging this depleted position, the 49ers will get a boost from the return of perennial All-Pro linebacker NaVorro Bowman.

Bowman’s knee injury is still not 100 percent healed. But the 27-year-old veteran is confident that he’ll be ready to go for the start of the season.

“The knee will get to where it needs to be,” Bowman said via Tyler Emerick of 49ers.com. “Maybe not as fast as you guys expect, but I’m definitely going to get back to that level.”

Joining Bowman up the middle will be linebacker Michael Wilhoite. Wilhoite primarily served as the team’s first-choice backup linebacker over the past two seasons. He spelled Willis amicably enough in 2013 and served as Bowman’s replacement last year.

“He’s a hard worker,” Bowman said of Wilhoite via Emerick. “He understands that he had to crawl before he could walk. … He’s doing a great job. The crazy thing is some of the things that I don’t know or don’t say, Mike says it. So it’s really working out.”

Wilhoite figures to be the starter alongside Bowman in 2015. Backing them up may fall upon the shoulders of linebacker Philip Wheeler. Or San Francisco could consider shifting outside linebacker Ahmad Brooks over to the inside.

Linebacker Michael Wilhoite will remain a starter after the offseason losses of Patrick Willis and Chris Borland. Mandatory Credit: Chuck Cook-USA TODAY Sports

Brooks broke into the NFL as a middle linebacker back in 2006, and the 49ers already have plenty of depth at the outside.


Will cornerback Dontae Johnson get the call for San Francisco’s second starting cornerback in 2015? Mandatory Credit: Kyle Terada-USA TODAY Sports

On a positive note, the 49ers have a lot of depth at the cornerback position despite losing the tandem of Culliver and Cox to free agency.

But the majority of this depth either lacks sufficient pro-level experience or does not inspire tremendous confidence after previous player campaigns.

Cornerback Tramaine Brock should return to his spot as the 49ers’ No. 1 corner. Deciding who plays alongside him in a base defense is another question.

Veteran cornerbacks Chris Cook and Shareece Wright could get the nod here based on their NFL experience alone. But neither have emerged as a legitimate force on the defensive side of the ball and, in particular, Wright has to be considered more of a liability than a bonus.

The nod could go to second-year pro defensive backs Dontae Johnson or Keith Reaser. Johnson flashed some promise his rookie season despite a rough finish to his efforts. And Reaser, who was redshirted his rookie year, was one of the standouts of San Francisco’s offseason programs per Grant Cohn of Bleacher Report.

Next: Who Will Actually Play Cornerback for the 49ers?

Then there is the question of the 49ers’ nickel cornerback. Jimmie Ward occupied this role until he was injured in Week 10. Prior to the injury, opposing quarterbacks posted a 138.2 passer rating according to Pro Football Focus (h/t Cohn).

The 49ers aren’t ready to give up on their first-round investment from the 2014 NFL draft. But Ward will certainly have to demonstrate some improvement in 2015 in order to avoid the “bust” moniker altogether.

Despite the notable losses San Francisco suffered on the defensive side of the ball this offseason, fans should take some comfort knowing that there is still plenty of talent to go around. This talent should ensure that the 49ers defense won’t be a significant liability heading into the regular season.

That doesn’t mean the unit is without question marks though.

While the D-line will go into its first season without Justin Smith, the knowledge of having tremendous depth here lends credence to Tomsula’s first line of defense having enough capacity to remain an effective group.

And the return of Bowman also takes some of the sting away from the losses of Borland and Willis.

The remaining concern is at cornerback. Mangini’s defense could wind up taking more gambles in 2015 which, although providing more opportunity, could expose lesser-talented players within the secondary. Should we expect defensive backs like Cook, Ward or Wright to be a liability? It’s hard to say.

Cornerback may be the biggest weakness on defense. But that doesn’t mean this position will be horrible either.

49ers fans are hoping this will be the case.

All statistics, records and accolades courtesy of Pro-Football-Reference.com unless otherwise indicated.

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