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Declaring that the San Francisco 49ers offensive line will rebound in a huge way in 2015 might seem as more of a trite statement rather than bold assertion.

After all, the 49ers surrendered the third-most sacks in 2014, with Colin Kaepernick enduring all 52 of them.

Notwithstanding Kaepernick’s own indecisiveness and poor pocket awareness, which accounted for seven of those sacks, per Pro Football Focus, San Francisco’s O-line produced a miserable campaign last year.

That said, the reasons for this unfortunate regression and corresponding hope for the immediate future still merit investigation.

The healthy return of two key assets, the departure of another and a renewed offensive philosophy under different coaching leadership will help restore the Niners’ corps of pass-blockers to their rightful upper-echelon standing.

It might just also help No. 7 stay off the turf more often than not.

With that in mind, let’s break down why the 49ers offensive line will bounce back to dominant form in 2015.

Exit Mike Iupati, Enter Brandon Thomas (and 2 Others)

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Again, call it obvious, but much of the reason for the awful pass blocking was on the shoulders of the 49ers’ starting left guard.

Mike Iupati coughed up seven sacks and 24 additional quarterback pressures in 15 games. Only one other guard and six total linemen allowed more sacks last season.

As great as Iupati was in run blocking (No. 2 among 78 rated guards), he was equally deficient in pass protection.

So it goes without saying that replacing Iupati with just about anyone else will improve the Niners' sack totals moving forward.

Who might those replacements be?

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Three different guys will compete for the vacant spot at left guard: free-agent addition Erik Pears and third-round picks Brandon Thomas and Marcus Martin.

Pears started all 16 games at right guard for the Buffalo Bills in 2014. Pro Football Focus ranked him two spots from the bottom at No. 76 with negative grades in both run and pass blocking.

Despite those unsightly marks, the 49ers gave Pears $1 million guaranteed as part of a two-year, $4.7 million deal “with the intention of having him compete for the starting job that became available when Iupati went to the Arizona Cardinals,” per Matt Maiocco of CSNBayArea.com.

Thomas and Martin, meanwhile, will also join the competition. The former rehabbed a torn ACL and didn’t play a single snap in 2014, while the latter started eight games at center. Martin did earn a negative overall score from PFF, but his future promise remains.

Marcio Jose Sanchez/Associated Press/Associated Press

ESPN Insider detailed in its draft evaluation that Thomas has “adequate lateral agility in pass protection” with a “power, length and...physical style” that will mesh well with the 49ers O-line. Those same scouts noted that Martin is “light on his feet and has a jarring punch in pass protection,” adding that “he should develop into a quality starter sooner than later.”

Here’s what Niners general manager Trent Baalke offered on the subject, via Maiocco:

Everyone has to earn their role, and it’ll be up to Erik to earn his role, just as it’ll be up to Brandon and Marcus Martin and [Daniel] Kilgore coming back off of injury...so there’s going to be some competition in the ranks. And as you’ve seen, we’re certainly open to drafting offensive linemen, and we’ll most likely do that again.

Our money’s on Thomas stepping up and realizing his first-round value. Expect far fewer sacks and pressures allowed as a result, with Martin serving as a valuable backup along the interior.

That leaves Kilgore at center and a stalwart on the right side of the line who will bolster this positional group for San Francisco in 2015.

Kilgore Returns to the Middle, Anthony Davis to the Right

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As mentioned, a certain interior mauler from Appalachian State will regain his starting role in the middle of this offensive line.

Daniel Kilgore defied expectations and beat out Martin in training camp last year. He started six games and absolutely excelled when on the field.

The fourth-year pro demonstrated impressive poise at the line of scrimmage, surrendering nary a sack and allowing just six quarterback hurries. PFF ranked him No. 13 among 41 of his league-wide fellows for his efforts.

Even though he remains a superior blocker in the run game, zero sacks and zero hits are noteworthy marks. They certainly speak to his dependability at the most important spot along the front line.

Unfortunately, a gruesome broken leg, suffered against the Denver Broncos during the second half in Week 7, ended Kilgore’s season much too early. The 49ers subsequently gave up 35 sacks over the next 9.5 games, more than double the mere 17 sacks recorded in 6.5 contests with him in the lineup.

Kilgore will surely earn back his starting spot come Week 1 of this season.

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Anthony Davis, for his part, battled injuries throughout 2014 and started just seven games at right tackle. When healthy, he allowed just three sacks, not to mention zero over his final three starts.

Jonathan Martin replaced Davis in those other nine games and, despite registering just 661 snaps, surrendered the fifth-most sacks among NFL tackles (six).

Martin found himself relieved of his duties not too long after the offseason began.

With a new face at left guard and the return of two big-time assets at center and right tackle, the 49ers will have all the necessary personnel in place.

And they’ll also have the coaches.

In Chris Foerster and Geep Chryst the 49ers Will Trust

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Excluding the passing game, former offensive line coach Mike Solari and offensive coordinator Greg Roman did an admirable job for much of their tenure together in San Francisco.

The 49ers climbed from eighth to fourth to third in rushing offense from 2011 to 2013. They fostered one of the elite run-oriented contingents in the league and steadily improved the play of the team’s pass-blockers as well.

That unit jumped from 25th to 23rd to 11th by reducing its sack totals from 44 to 41 to 39 respectively during that span.

Then 2014 happened—and it all came crashing down.

The 49ers ranked three spots from the bottom by allowing those aforementioned 52 sacks. Although their rushing attack stayed in the top five, the coaching staff didn’t consistently put the blockers up front in a position to succeed and do what they do best—i.e., maul in the trenches.

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Pass protection suffered as a result, not to mention San Francisco ranking 21st, having scored just 10 rushing touchdowns.

Fortunately for the 49ers faithful, help is on the way.

Andrew Pentis of the team's official website notes that former O-line coach Chris Foerster is back to “both help the 49ers running game return to its usual heights while also cleaning up the unit’s pass protection.”

Pentis adds that Foerster helped the Washington Redskins lead the NFL in rushing yards per game in 2012 and kept them high up at No. 5 in 2013. Washington also ranked in the top half of the league in sacks allowed during that period.

The promotion of Geep Chryst to offensive coordinator, meanwhile, will further elevate this 49ers offense.

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Senior reporter Taylor Price of the 49ers' official website states that “the team's former quarterbacks coach of the past four seasons will look to simplify San Francisco's offensive playbook.” He’ll do so by streamlining the approach.

Here’s how Chryst himself discussed how he’ll facilitate that change:

We know that these rosters are churning more and more than they ever have. ... In 2015, we’re going to have a new roster compared to what we had in 2014. So how I see my role within that, is having a system that they can easily digest in our shortened offseason, nine weeks, seven with the coaches out on the field.That’s not much time to try to have a major overhaul, but we’ve got to teach the young players how to fit in with our veterans.

And knowing that Chryst loves the Niners’ free-agent acquisitions and “players that [they] have coming back,” fans should surmise a return to a ground-and-pound offense behind running backs Carlos Hyde, Reggie Bush and Kendall Hunter.

To that end, Foerster and Chryst will redirect the offensive line toward its run-blocking strengths. This positive change will help keep Kaepernick upright and open up play-action opportunities deep downfield for Torrey Smith and other Niners pass-catchers.

Then again, can fans trust that this transition will actually happen? Well, to an extent, they must—that’s what being part of a “faithful” fandom is all about.

But like Taylor said, “to really know to what degree things will change, we'll have to wait until games are played in September.”

All team and player statistics courtesy of Pro-Football-Reference.com and NFL.com unless otherwise noted. Advanced metrics provided by Pro Football Focus.

Joe Levitt is a featured columnist for Bleacher Report, waxing academic, colloquial and statistical eloquence on the San Francisco 49ers. Follow him on Twitter @jlevitt16