How Can Eric Mangini Get Most out of 49ers Defense in 2015?

Despite the flurry of offseason changes that have fallen upon the San Francisco 49ers, defensive coordinator Eric Mangini's defensive squad appears to remain in good shape heading into the 2015 NFL season.

It's a bit of a conundrum. How can a defense—one that lost defensive end Justin Smith, cornerbacks Chris Culliver and Perrish Cox and linebackers Patrick Willis and Chris Borland—wind up replicating the same level of play for which the 49ers have been known for a number of years now?

But the defense will live up to that standard as long as Mangini has anything to say about it.

The newly minted coordinator will have tough shoes to fill. He will be tasked with meeting the bar set by former defensive coordinator Vic Fangio, whose defenses ranked in the top 10 during his four seasons in San Francisco.

Despite the offseason upheaval, the 49ers defense figures to remain a strength under Mangini and head coach Jim Tomsula. After all, San Francisco spent its first three picks of the 2015 NFL draft on defensive players.

And younger cast members are poised to fill the voids left by departing veterans.

So what should we expect Mangini to do with his defense? Who will the starters be and which players will be the linchpins of San Francisco's defensive efforts?

Kyle Terada-USA TODAY Sports

Mangini's Scheme

The new defensive scheme under Mangini will likely be more aggressive than what was under Fangio.

There are some similarities, though.

At its base, the 49ers will continue to run a 3-4 defense. But there will be some notable differences between the two.

In some ways, the new defense may focus on hybrid players who aim to confuse opponents' offenses. This is the argument made by Oscar Aparicio and David Neumann of the Better Rivals podcast via Niners Nation.

But at the same time, Aparicio notes that Mangini will rely on similarities seen under Fangio:

Yet, Fangio didn't blitz often. Should we expect Mangini to dial up more elaborate blitzes to create additional pressure up front?

We can draw up a side-by-side comparison on how this might work.

Let's go back to Week 15 of the 2014 season, when the 49ers were visiting the Seattle Seahawks. Two similar defensive alignments shall be the case study. One is a blitz package, while the other is not.

On the first play, we can see four men up in the box with additional pressure seemingly applied from the linebacker spot.

Credit: NFL Game Rewind

One inside linebacker will actually rush toward quarterback Russell Wilson, while the outside pass-rusher on top will actually drop back into coverage. 

Credit: NFL Game Rewind

This is still a four-man rush, which allowed additional defenders to guard against the aerial attack. Wilson tossed an incomplete pass to his left. It is basic, simple football.

But on this play, later in the quarter, Fangio brings six pass-rushers into the fold. The look is the same from the previously dissected play, with six men toward the front. But all six will participate in the pass rush, and interior pressure will open up an opportunity for former 49ers defensive end Ray McDonald to record the sack on Wilson.

Credit: NFL Game Rewind

Credit: NFL Game Rewind

This attempt is a little more elaborate. And it certainly exposes the secondary, provided that the pressure cannot reach the quarterback in time.

Still, it's confusing as long as the pass-rushers are doing their job effectively.

The goal is to create an overload of confusion on offense—an aspect that Mangini himself has emphasized, per Matt Maiocco of CSNBayArea.com.

But it's an approach that may also open up problems. Maiocco wrote:

"

The 49ers’ ideal is to create confusion for the opposing offense, and that should lead to more big plays for the defense. However, it is also likely to create more confusion for the 11 players on defense and result in more big plays going the wrong direction, too.

"

Thankfully, the 49ers have had all offseason to hammer out the details. Mangini's optimistic about the offseason results, per Scout.com's Chris Biderman:

All-Pro linebacker NaVorro Bowman is one such player who admitted, per Maiocco, that the new scheme will take some getting used to:

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We’re asked to do a lot more than we were. It has its ups. The only downs are that we weren’t used to it. But as we continue on throughout the weeks, getting used to talking a little more than we did in the past, we’re all getting on the same page and it’s working out.

"

Now, the true test will be whether or not the transition and learning process will provide effective results.

Rick Scuteri/Associated Press

The Starters

San Francisco will employ a number of new names on defense in 2015.

Many of these are intended to replace veterans who left the franchise either via retirement or free agency. And there are some noteworthy shoes to fill.

The biggest are, without doubt, within the front seven. Borland, Willis and Smith are gone now, and the front seven would appear to be a weakness in the eyes of those who do not understand the 49ers depth.

Thankfully, a new cast of players is poised to make its mark.

Veteran defensive lineman Darnell Dockett will bring his talents to the mix, while third-year pro Tank Carradine will look to replicate the same type of production made by Smith along the line. 

And, while Willis and Borland's retirements cannot be understated, San Francisco will benefit from Bowman returning healthy.

Jeff Chiu/Associated Press

Bowman will likely be joined by linebacker Michael Wilhoite who, while not as heralded, has performed amicably in a reserve role for the 49ers over his four-year career.

At outside linebacker, Aldon Smith will hopefully benefit from an offseason that was free of off-the-field incidents. His pass-rushing prowess should improve because of this. Joined by a combination of outside linebackers Aaron Lynch and Ahmad Brooks, the 49ers certainly have some likable depth here.

And the D-line will likely employ a rotation of players such as Carradine, Dockett, Glenn Dorsey, Ian Williams, Quinton Dial and others in order to give players added rest and provide various packages to which opposing offenses will have to adjust.

Chris Humphreys-USA TODAY Sports

But the situation in the secondary isn't quite as certain.

True, safeties Eric Reid and Antoine Bethea will be starting in Week 1, provided injuries aren't a factor. And Tramaine Brock is probably going to be the No. 1 cornerback. But who starts opposite him in San Francisco's base defense?

Will it be four-year veteran cornerback Shareece Wright? Or will the 49ers employ a developing corner like second-year pros Dontae Johnson and Keith Reaser? Battles such as these will only be determined by who performs best during training camp and in the preseason.

An early projection might look something like this:

• DE: Tank Carradine, Darnell Dockett
• DT: Ian Williams
• ILB: NaVorro Bowman, Michael Wilhoite
• OLB: Aldon Smith, Ahmad Brooks
• CB: Tramaine Brock, Dontae Johnson
• S: Eric Reid, Antoine Bethea

Being named a starter on the D-line might not mean that much. One should expect plenty of rotation up here given the position's depth. And one might even see a little bit of rookie defensive end Arik Armstead sprinkled into the mix as the first-round pick looks to develop his skill set.

And Lynch will assuredly get his snaps in more traditional pass-rushing roles. The same could be said of rookie linebacker Eli Harold.

But the backfield is the question mark, especially at cornerback. Fortunately, the 49ers can call upon a sizable amount of depth here as well.

Jeff Gross/Getty Images

Impact Players

Bowman's return is one of the numerous reasons why 49ers fans should be excited about the defense. Over a year removed from his horrible knee injury, Bowman is already emulating his All-Pro form.

Taylor Price of 49ers.com noticed how effective Bowman was during minicamp:

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Bowman didn't hit anybody, but he was in position to smother the running backs on nearly every run play. Bowman hasn't played in a game since January of 2014. Even so, the stud linebacker's instincts appear to be as sharp as ever. When the 49ers worked on goal-line run plays, Bowman was in the hole waiting for the ball-carrier.

Bowman's left knee brace was only utilized during team drills. The sixth-year pro ditched the brace for individual warmup drills. It's not known if Bowman will continue with the brace throughout training camp. But one thing is for sure, Bowman's three-day camp showed everyone that he's continuing to progress this offseason.

"

A 90 percent Bowman is still one of the best players in the league, so it's safe to assume that any lingering injury effects won't significantly hinder his efforts on the field.

That's good. And the news gets better.

Expect a big season out of Lynch. The second-year pro tabbed six sacks last year—tied for the team lead (Brooks)—and now has one full season of experience under his belt.

But the biggest pass-rushing threat remains Aldon Smith.

Joe Fann of 49ers.com pointed out that Smith is "thriving" under the new system. And Smith has already done plenty of preparatory work to get himself back to an elite level.

“I feel fast now,” Smith said, per Fann. “I’ve lost some weight, slimmed up, gotten stronger, and it’s shown on the field.” Smith went on to simply say, when he's playing well, he "can't be stopped," also per the team's official website:

Yet much of Smith's success relied on the ability of Justin Smith to open up opportunities for him. When the elder Smith went down with an injury in Week 14 of the 2012 season, Aldon Smith's sack totals dropped significantly. He was unable to record a single sack with the veteran end in the lineup.

Similarly in 2014, a banged-up Justin Smith was not able to create the same opportunities for Aldon when he returned from his nine-game suspension.

Smith finished the year with just two sacks.

This puts increasing pressure, not on Smith, but on Carradine. The prolific collegiate pass-rusher has yet to make a serious impact at the NFL level. 

But his best role might be filling the void left by Justin Smith. Maiocco goes into further detail:

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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.

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Hopefully Carradine will fit the bill.

If the pass-rushers are doing their job up front, life in the secondary should be that much easier. But a change in blitzing schemes could alter the makeup and talents of the defensive backs. 

More blitzes means fewer players dropping into coverage. That can expose more mistakes. 

But it can also create more opportunities.

Such may be the case for the 2015 49ers. Mangini's defense will look to create the confusion without confusing itself.

If that approach works, San Franciso's offense won't slip from the lofty rankings it has enjoyed in recent seasons.

But that is a significant if.

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

Peter Panacy is a Featured Columnist for Bleacher Report, covering the San Francisco 49ers.

Follow him @PeterPanacy on Twitter.