49ers loss vs. Chiefs showed why offensive line is a liability

The 49ers didn’t play all their starters against the Chiefs on Saturday, but many of the backup offensive linemen gave a noticeably poor performance.

While the overwhelming majority of focus from the San Francisco 49ers‘ 19-16 preseason Week 1 loss to the Kansas City Chiefs on Saturday night focused on rookie quarterback Trey Lance, a growing bit of attention has started to center on the Niners offensive line.

Granted, San Francisco elected to sit left tackle Trent Williams and center Alex Mack, and the remaining starters ended up seeing only a handful of offensive drives before giving way to the second-, third- and even fourth-string unit.

Lance, however, spent a significant portion of his two-plus quarters evading pressure from the Chiefs defense, taking four sacks over the game, the first coming at the hands of Kansas City defensive tackle Chris Jones who bulled over starting right guard Daniel Brunskill.

To his credit, and showing signs of maturation, Lance told reporters after the game how his four sacks resided on his shoulders, not on his O-line, which went through the usual changes throughout the exhibition matchup.

In some way, Lance is correct. One, arguably two of the sacks could have been avoided, either by Lance getting rid of the ball sooner or by using his legs to evade pressure.

But with head coach Kyle Shanahan looking to keep Lance from relying on his legs in his first NFL action, sacks were going to happen.

Unfortunately, the 49ers’ O-line depth isn’t exactly looking to be promising early on in 2021.

49ers O-line depth might be the biggest worry

Again, it’s hard to judge preseason action as a true indicator of how any unit will do. Plus, with the Niners resting two-fifths of their starting O-line right out of the gate, an accurate assessment is nearly impossible.

But let’s look at Pro Football Focus’ game grades for the starters:

• LT Jaylon Moore: 60.5
• LG Laken Tomlinson: 51.7
• C Jake Brendel: 58.4
• RG Daniel Brunskill: 55.9
• RT Mike McGlinchey: 54.1

Moore, the rookie, getting the best grade out of the bunch is interesting. But he was also credited with two of the 12 total pressures allowed from the game.

Backup lineman Corbin Kaufusi and swing-tackle candidate Shon Coleman were also credited with two pressures apiece, while second-year pro Colton McKivitz allowed one as well. Kaufusi and Coleman might not make the 53-man roster, but one might expect San Francisco to have high hopes for McKivitz.

Looking back at the game, McKivitz appeared to hold his own in run blocking, but his pass-protection efforts still left a lot to be desired.

Should 49ers worry about Aaron Banks yet?

The 49ers’ second-round pick from this year’s NFL Draft, offensive guard Aaron Banks, has had himself a relatively sluggish training camp and doesn’t appear poised to take over the starting right guard position over Brunskill just yet.

And looking at Saturday’s game, it might not happen anytime soon.

Banks allowed the most pressures (four) of any Niners O-lineman, earning a paltry 29.8 PFF grade in the process before exiting the game with a shoulder injury. Shanahan later told reporters Banks is expected to miss two to three weeks, which essentially wipes out the rookie’s preseason campaign from this point forward.

Valuable reps for experience are now gone.

Granted, Banks was more of a power lineman during his time at Notre Dame, and it was generally understood he’d need some adjustment to Shanahan’s outside-zone scheme. But with Banks’ early struggles in training camp and now in the preseason, signs are pointing to a much longer development time with him, thereby forcing the uber-versatile Brunskill back into a starting role instead of him being a high-quality reserve for essentially any spot along the O-line.

Read More: Is 49ers O-line depth emerging as a problem?

It’s far too soon to consider Banks a busted pick, of course. Yet it’s safe to worry a little bit about a slower development.

True, Banks starting off his rookie season as a reserve might not be the worst-case scenario, and it’s not quite doom-and-gloom time for San Francisco’s O-line, especially with players like Williams and Mack awaiting their first snaps of 2021.

Yet it’s fair to worry a little bit about the team’s overall depth, even among those who wind up making the 53-man roster this season.