State of the 49ers: Fixing Brock Purdy’s offensive line starts with one big investment

Welcome to Part 1 of our eight-part State of the 49ers series — where we’ll assess each position group and introduce some high-level solutions to get the team back into next season’s Super Bowl hunt. First up: the offensive line.

Outside of quarterback Brock Purdy, no group of players is more vital to the 49ers’ offensive success. And yet the offensive line might be the messiest group to evaluate this offseason due to shifting needs across the five positions and head coach Kyle Shanahan’s unique demands for the unit.

There’s been a tendency to oversimplify the 49ers’ performance here over the years. “Shanahan doesn’t invest in the unit” and “the 49ers were terrible up front in 2024” are common tropes. But these ideas are based on half-truths at best.

The 49ers actually have invested in their offensive line — they’re in the upper half of league spending at the position — and, cumulatively speaking, they might’ve actually been slightly above-average performers there in 2024, especially considering the fact that there’s been a league-wide malaise in O-line play.

But that doesn’t eliminate the need for more investment and improvement up front, particularly with the 49ers set to double down on Purdy — perhaps with the largest contract in NFL history.

Let’s set the table for that with a jarring graphic from the 2023 season, when Purdy was an MVP finalist posting borderline historic efficiency numbers — all while the 49ers ranked No. 24 in Pro Football Focus’ cumulative pass-blocking grade.

QB efficiency is plotted on the vertical axis. Team O-line grade is plotted on the horizontal axis. The simple conclusion, based on Purdy’s positioning as an outlier in the upper-left quadrant: Fix the offensive line in front of this guy to ensure that top-notch QB play is sustainable.

So the 49ers aimed to do that in 2024, and in some ways they were successful. They climbed all the way to No. 11 in PFF’s cumulative pass-blocking grade. The right side of the line — which was horrid in 2023, with tackle Colton McKivitz and guard Spencer Burford starting the majority of games — made a huge stride forward after rookie Dominick Puni replaced Burford. Collective improvement, measured by PFF’s pass-block efficiency (which tallies pressures, hits, and sacks allowed) and ESPN’s pass-block win rate (which measures how often a line holds its blocks for 2.5 seconds or longer), was evident.

But despite registering top-half marks, the 49ers languished in other areas.

A rash of injuries to their offensive skill position weapons, most notably receiver Brandon Aiyuk and running back Christian McCaffrey, led to massive separation issues. Per NFL Next Gen Stats, the 49ers ended up ranking dead last, No. 32, in average separation generated at the time of catch or incompletion — a regression from No. 11 that effectively eliminated any efficiency benefit that improved pass protection could generate.

And, of course, the 49ers’ O-line itself didn’t make linear progress. While the right side improved enough in pass protection to make cumulative scores better, the left side of the unit — from center Jake Brendel to left guard Aaron Banks to left tackle Trent Williams — took steps back in 2024.

Williams initially played through an injury that eventually ended his season. The 36-year-old continues to perform at a high level, but the 49ers need him healthier to consistently protect Purdy’s blind side moving forward.

“He had a bruise in the ankle joint, and it probably took a little longer than anyone anticipated, but sometimes that happens,” 49ers general manager John Lynch said this month. “And the good news is that it’s taken a positive turn.”

If history is any indication, the 49ers will move on from Banks — a pending free agent — at the left guard spot. They didn’t re-sign his predecessor, Laken Tomlinson, when free agency rolled around in 2022. Guard has not been a big-money position for the 49ers. They’ve relied on either draft picks — Puni was fantastic on the right side before hitting a rookie wall in pass protection to close the season — or budget-friendly veterans there.

Perhaps Ben Bartch, who briefly filled in for Banks before suffering a season-ending injury of his own, can fit the bill. Bartch, 26, played very well in limited action, but the 49ers must work to re-sign him since he’s also a pending free agent. The 25-year-old Nick Zakelj, who was great in pass protection over 162 fill-in snaps but must still improve his run blocking, is another option at both guard and center. (More on the very vital future of that position below.)

The improvement of Burford — the former starting right guard who saw reserve action at both guard and left tackle (the position he played in college) — in pass protection was a notable development. He’d ranked in just the second percentile as a rookie but surged to the 58th percentile in year two. Given the limited roster sizes of the NFL, it’s imperative for teams to field passable and versatile O-line depth. There’s reason to believe Burford can continue developing into a sixth- or seventh-man option.

To most fans, Brendel and McKivitz are the two most polarizing players on the front, but their duties and performance within the context of Shanahan’s system are significantly different.

McKivitz, by any measure, enjoyed a year of significant improvement. Puni’s presence to his immediate left might’ve played a big role in that. The 49ers are now enjoying middle-of-the-pack right tackle play at about $6 million per year, which is undeniably good value by modern NFL standards.

Sure, the NFL draft offers potential upgrades to McKivitz and potential down-the-road successors for Williams — LSU’s Will Campbell is the most popular name — but acquiring blue-chip O-linemen when demand for them egregiously outweighs supply can be exceedingly difficult. Campbell, after all, is projected to be a top-five pick.

“There’s not a lot of people who have the skill set to play tackle, so it reduces the pool,” 49ers director of player personnel Tariq Ahmad said after the 2024 draft. “We are very selective of those guys.”

Perhaps a more realistic path to both short- and long-term results lies in drafting a less developed O-line prospect — think Missouri’s Armand Membou or North Carolina State’s Anthony Belton, who has definite guard potential with the possibility to develop as a tackle.

Then there’s the very important center position, which Brendel has manned since 2022. Center is especially vital in Shanahan’s system since it’s tasked with identifying safety rotations, setting protections, and executing difficult reach blocks that are indispensable to the outside-zone rushing attack. This is why Shanahan has gone after high-priced centers in the past — the 49ers have added both Weston Richburg and Alex Mack since 2017 — and why he should be interested in upgrading that position now.

Brendel was an above-average pass protector in 2022, but his play has regressed over the past two seasons, and the 49ers can clearly use the elevating effect of a star at the center position. A rising tide, especially one at the fulcrum of the offensive line, lifts all boats.

With that in mind, the 49ers signed Matt Hennessy, who’s under contract through 2025, off the Atlanta Falcons’ practice squad late in the 2024 season. Hennessy succeeded Mack as the starting center in Atlanta and was later replaced by Drew Dalman, who’s scheduled for free agency come March. The 49ers can potentially make a run at a veteran scheme fit like Dalman, or they can allow Brendel and Hennessy to compete for the starting job while shepherding a rookie — Texas center Jake Majors is a prospect to watch — into the mix for the future.

Only this much is clear: Center is a position that a rookie would have a tough time filling under Shanahan. That’s how cerebrally demanding it is. But it might mark the most efficient pathway to improvement of the 49ers’ offensive line, which has been a variable behind some growing issues over the past two seasons.

The first is rushing efficiency, which slid precipitously in 2024.

The injuries to McCaffrey and other 49ers running backs factored into this slide, of course. But so did blocking struggles on the interior and on the left side, where Williams’ typically dominant presence was absent for most of the season. Without delivering an efficient ground game on first down, the 49ers offense suffered downstream regression.

That must change in 2025, and the clearest path to do so appears to be via earnest work at both center and left guard. Improvement there, in turn, can further boost the 49ers’ pass protection.

Make no mistake: The team took some important strides when it comes to protecting Purdy in 2024. But the 49ers also slipped in some key areas, and the complementary world of football demands that all puzzle pieces are in place. This offseason is about finding the missing ones while ensuring there’s no slippage among established pieces this time around.

The 49ers on Monday hired Brant Boyer to be their special teams coordinator. He replaces the fired Brian Schneider, who presided over the NFL’s worst special teams unit in 2024.

Boyer coordinated the New York Jets’ special teams unit from 2016 to 2024. He’ll be tasked with helping turn around a 49ers group that lost a staggering 63.8 expected points on special teams — one of the worst marks on record — last season.