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Film room: Breaking down the key mistakes that plagued the offense

Film room looks at Nick Mullens and the offensive line struggles versus the Eagles in week 4.

Philadelphia Eagles v San Francisco 49ers Photo by Ezra Shaw/Getty Images

Nick Mullens made his second start of the season, and any hopes of a quick and easy victory were quickly dashed on the game’s opening drive for the 49ers offense as he failed to connect on two wide open passes. Wild overthrows that would unknowingly foreshadow how the rest of the game would play out. He finished the game with 200 yards passing, one touchdown, and two interceptions, a drastic turn from his impressive showing in week three against the Giants.

So what happened?

After re-watching the game and then going through the all-22, it’s clear that both Mullens and the offensive line were the primary culprits of the poor outing. When Mullens dropped back to pass, on several occasions, he had pressure in his face and couldn’t escape the impending sacks. And when the line did give Mullens time, he overthrew receivers and threw two costly interceptions, including one for a pick-six.

Shanahan said right from the start, the plan was to get Mullens into a rhythm and that they tried several times and just couldn’t get it going. “We started with two passes and missed both of them and thought we’d give him a chance to get going, get him into a little bit of a rhythm. It seemed like whenever we did something else came up and just wasn’t able to get him much into a rhythm.”

That’s putting it mildly, but it wasn’t all Mullens. So let’s look at where things went off the rails.

Mullens off-target often

On the first two plays of the game, Shanahan schemed up some wide-open throws that are as basic as any quarterback can reasonably be expected to complete in Shanahan’s offense. The first throw was “Dragon Y Over,” and the second throw was a fullback leak off play action that we have seen numerous times from Shanahan over the last three seasons.

Dragon Over is a basic slant/flat concept with the tight end running an over the ball route. Under center, it’s a 3-step drop and throw. From shotgun, it’s practically just catch the snap and throw. All Mullens is reading is the linebacker dropping to the flat or dropping underneath the throw. He makes the correct read, but the throw is too far in front of receiver Kendrick Bourne.

Mullens missed a wide-open Kyle Juszczyk running out of the backfield on a leak route down the numbers on the very next play.

I think this may have been the first time in three-and-a-quarter seasons that a Shanahan quarterback has not completed this most basic of throws. The linebacker to the weak side is responsible for fitting the fullback on the run, and by the time he realizes it’s a pass, Juszczyk is already 10 yards downfield with linebacker Nate Gerry having to pick up the slack. If Mullens connects, that’s at a minimum a huge gain and possibly a touchdown.

It was the correct process on both throws, throwing to the open receivers, but he just couldn’t connect on them. But Mullens’s first truly bad decision came on a drive in the second quarter when he had already converted a big third-down throw to tight end George Kittle down the sideline.

The play call is a play-action pass with a deep crosser, and a sideline go route. Mullens executes the fake and turns to look for the crosser but has a rusher in his face and hurries his throw. The pass was intercepted, but it didn’t need to be. He should’ve just thrown it away.

In the fourth quarter, when the 49ers went down 18-14 after Mullens fumbled, he had a chance to lead a long fourth quarterback comeback drive with just under six minutes left in the game.

The play call is a 7-step two-man concept, “both dig,” which is just a deeper curl route. The Eagles are in quarters coverage. Mullens hits the top of his drop and throws to Brandon Aiyuk (No. 11) on the left sideline, but he didn’t see the linebacker dropping down to the flat under the curl route because there was no route occupying the flat defender.

On seeing the Eagles rotate toward the short side of the field, Mullens should’ve hitched and thrown to the wide side. At a minimum, the play might have been broken up instead of intercepted.

Offensive line breakdowns

The offensive line did not play well either and had their moments where, as Shanahan said above, as they tried to get Mullens in a rhythm, “something else came up.” That “something else” was, more broadly, the Eagles defensive line.

Right away, the 49ers offensive line had trouble containing the Eagles’ rush.

First-quarter, 9:16, 2nd-and-15

On this 2nd-and-15 play from the first quarter, the Eagles don’t do anything exotic or difficult. They just simply beat the man in front of them. Left guard Laken Tomlinson (No. 75) and left tackle Trent Williams (No. 71) just get beat on the play.

Javon Hargrave (No. 93) and Derek Barnett (No. 96) share the sack with a pass rush from the defensive line’s right side. Hargrave gives Tomlinson a club-and-swim to the inside and wins immediately. Williams gets bull rushed into the backfield by Barnett. Mullens initially dodges Hargrave but slides right into Barnett’s rush, where Hargrave and Barnett take him down.

Fourth-quarter, 15:00, 1st-and-10

Later at the start of the fourth quarter, Trent Williams gave up another sack when he couldn’t contain the rush of Josh Sweat (No. 94).

Sweat fights to get his pads lower than, and inside of, Williams and sort of uses a bull fork rush to knock him into the backfield. It looks like Williams gives up on the rush as Sweat stumbles a bit, but Sweat keeps his balance and chases Mullens into the backfield before he finishes with the sack.

Fourth-quarter, 10:06, 3rd-and-10

On the next drive, the 49ers gave up another sack when Cre’von LeBlanc beat Dan Brunskill (No. 60) to the outside on as the fifth defender adding the fire zone blitz.

The Eagles sent a fire zone blitz on 3rd-and-10, as they had done a few times previously throughout the game to mess with the 49ers protection schemes. The line actually blocks it up quite nicely this time except for Brunskill. McKinnon picks up the middle rusher, and the 49ers have a 3-on-2 to the left side of their line, leaving Brunskill alone with a smaller, faster defensive back.

Brunskill lunges to block, and from there, the rep was lost. He never recovered good enough to ride LeBlanc past the pocket. It even looks like he got away with a hold as he pulled on LeBlanc’s arm. LeBlanc goes for the sack and ends up hitting the ball out of Mullens’ hand with his helmet.

Eagles fire zones messing with 49ers scat protection

Several times throughout the game, the Eagles sent fire zone blitzes at the 49ers scat pass protections. Scat pass protections tell the offensive line they are not going to have help from the tight end or running back because they are going to release immediately into pass patterns.

The first 3rd down of the game gave a glimpse into how the Eagles might counter 49ers spread formations on third and long. Fire zone blitzes can be very effective at manipulating and confusing offensive linemen even though the defense generally just sends one extra rusher at the quarterback. The problem is an offense can never really know where that extra rusher is coming from.

The 49ers have a three scat protection called, meaning the protection slide is to their right. Brandon Graham is the defensive lineman dropping into the low hole, and Nate Gerry is the linebacker adding to the rush. The breakdown comes when the defensive line slants to their left, into the protection, and takes advantage of the offensive line’s slide to the right.

On scat protection, the tackle (Williams) to the call side (where they declare the MIKE) is responsible for containing the edge rush with Tomlinson’s responsibility being the next rusher through, so he should be watching for Gerry (No. 47). But he sticks with blocking the slanting defensive tackle and is turned nearly perpendicular to the line as Gerry rushes into the wide-open B-gap. The rush forces Mullens to get rid of the ball quicker than he’d like to Kittle, who catches it and has no chance to get the first down.


The 49ers have a lot to clean up in pass protection as it has not been great. By no means is it bad either, but it’s just bad enough that their back-up quarterback cannot carry the 49ers for an extended period of time. Hopefully, getting Garoppolo back can alleviate some of the issues, but the schedule isn’t getting any easier over the next seven games after Miami.

It’s also unclear who will start at quarterback against Miami. Still, if Garoppolo can’t go, I would feel confident in saying C.J. Beathard will more than likely be named the starter for Week 5 because he gives Shanahan the ability to push the ball downfield a bit better than Mullens. As of Wednesday, though, Garoppolo was listed as a limited participant in practice, which is a bit of good news. In either case, they’ll need the offensive line to start playing better as a unit if they’re going to be able to sustain any close games with their upcoming schedule gauntlet.