How Rams Defense Shut Down the 49ers

NFL Conference Championship - Although defensive coordinator Brandon Staley left the Rams following the 2020 season, his imprint on the defense has remained. Raheem Morris was hired from the Falcons to replace Staley, but not his scheme. The Rams were adamant about keeping the two-high safety defensive structure that Staley had so much success with in his one season in L.A. They did not want to let it go, even if it meant forcing Morris to carry out a defensive vision that was not necessarily his.

And for the most part, it worked. The Rams retained a Staley-esque two-high defensive structure with extra bodies on the interior, lighter players at outside linebacker, and frequent deployment of just one inside linebacker. Some fixtures were different here and there, in part because of the secondary personnel the Rams hemorrhaged during the offseason, but Morris put together an objectively successful Staley imitation, netting the Rams a fifth-place finish in defensive DVOA.

Morris threw that out the window against San Francisco in the conference championship round. Rather than stick to what got them there, Morris and the Rams switched up their approach. Per Next Gen Stats, the Rams loaded the box and called single-high coverages at a higher rate against the 49ers than in any other game over the past two seasons.

The #Rams defense broke tendency in their NFC Championship win over the 49ers by showing more single-high safety looks, and loading the box to stop the run (i.e. box defenders > blockers):

🔹 63% Single-High (season-high)
🔹 49% Loaded Box (season-high)#SFvsLAR | #RamsHouse pic.twitter.com/oBbiqyZzps

— Next Gen Stats (@NextGenStats) February 1, 2022

As with anything, there are a few reasons the Rams may have wanted to do that, but the results showed up best against the run. With the loaded boxes, as well as some late rotations down into the box after the snap, the Rams were consistently able to have equal or favorable box counts. Typically when that is the case, the defense will try to force runs back inside with their fits, since that is where their extra help is located.

Run fits can also be simplified when the defense is not playing outnumbered the way the Rams usually are, which meant linebacker Troy Reeder in particular was able to play downhill a tick faster than usual and get after all of San Francisco's lead blockers. The added bodies in the box, the confidence to fit faster into a gap, and the Rams' outside linebackers always being aligned to handle the "widest of the wide" meant the Rams were essentially able to funnel plays onto the shoulders of Aaron Donald and A'Shawn Robinson in the B- and C-gap areas. Morris deemed that the best approach against a 49ers offense that loves to attack the perimeter with stretch runs and the C-gap area with pulling plays, and he was right.

Things got rolling on the first play of the game with the 49ers trying to run counter to the strong side of the formation with the tight end down blocking. Los Angeles has extra bodies in the box with Eric Weddle (20) rolled down near the line of scrimmage, which should mean that the Rams can get one man in every gap. Well, having Robinson (94) at defensive end outside the tackle helps change the matchup in the Rams' favor even further. George Kittle (85) would normally be able to handle blocking down on defensive ends from this alignment, but Robinson has the clear body-type advantage. Robinson is able to take on Kittle from his inside shoulder before immediately tossing him to the side and working to the outside shoulder, effectively getting two gaps for one player. Von Miller (40) and Reeder (51) both fit outside of their blockers to force the play inside to Robinson, who gobbles up the runner with Weddle sliding in behind him as a free hitter.

Make no mistake, Robinson more than held his own against blockers his size as well, including All-Pro Trent Williams. Every time the 49ers tried to attack the offensive tackle area towards Robinson, he refused to give them anything.

Williams almost gets off the ball quickly enough to fight across Robinson's (94) shoulders and turn him inside, but almost ain't good enough with the way Robinson has been playing lately. Robinson knocks Williams back a step (a rare feat for any defender), then extends his arms and fights for leverage outside of Williams. With backup outside linebacker Justin Hollins (58) doing a decent job coming up and taking it to the lead blocker, Deebo Samuel's (19) only options are to force himself through the nonexistent rushing lane Robinson and Hollins have sealed off, or cut all the way up inside from an awkward angle into a sea of bodies. Lose-lose.

At different points in the game, the 49ers tried to adjust and avoid Robinson. Running at Donald is not a particularly enjoyable endeavor either, but it's hard to suddenly have a 320-pound C-gap defender like Robinson sprung on you as an offense when that is not what you are used to dealing with. As such, the 49ers had to test the waters against Donald a bit, and it went exactly as anyone would expect it to.

In the following play, the 49ers try running counter to the weak side. With the Rams regularly aligning Donald to the weak side as a 3-technique and Robinson to the strong side as a 5-technique, the 49ers had to at least attempt to avoid the body-type mismatch Robinson was giving them. In theory, it makes some sense. Williams is massive and Donald isn't. In reality, all this did was show perfect unison between the Rams' outside fitters playing fast to funnel plays into one of their stud defensive ends.

Two things allow the Rams to squeeze this rushing lane to give time for Weddle (20) and Robinson to (94) clean up the play. The obvious is Donald (99) being Donald. Nobody should be able to feel a downblock, immediately redirect their momentum, and use their inside leg as a kickstand to firmly hold their ground against Williams while at a 40-pound disadvantage. It is superhuman. Second, the way Reeder (51) takes on the puller helps out the rest of the fit. Rather than fighting to the lead blocker's outside shoulder to get a free outside arm in that gap, Reeder basically takes the puller head-on with the sole purpose of knocking him backwards. Knocking back the puller lets Reeder take away the outside path with force while helping pinch the inside rushing lane because he is not playing the outside shoulder. The final product is the runner having to slam it right up into a box where the Rams feel good about the numbers they have.

From a vibes perspective, the nail in the coffin for the 49ers' run game was that even the Rams' backups were a force up front. When even a team's second-rate dudes are taking over, it is not the offense's day. Robinson and Donald rarely came off the field in base personnel, but when they did, guys such as Marquise Copeland stepped up to make plays.

Copeland (93) is playing in the B-gap opposite of Robinson, just as Donald would if he were on the field. It makes perfect sense that the 49ers would try to attack him as a reprieve from running into the teeth of the other two guys who have been beating them up all day. To Shanahan's dismay, Copeland and the rest of the front fit things up perfectly anyway. Backup outside linebacker Ogbonnia Okoronkwo (45) makes sure to get as wide as possible to deter any bounce to the perimeter, putting the onus on Copeland to win against his block and cut the play off properly. Perhaps thanks to wider alignment closer to the tackle than the guard, Copeland is able to easily fire through the guard's outside shoulder and cut the play off, pushing the runner back into the waiting arms of Weddle, Reeder, and Leonard Floyd (54).

The 49ers finally hit on a few decent inside runs towards the end of the game, but it was too little, too late by then. San Francisco failed to find a single carry beyond 10 yards, lead running back Elijah Mitchell never took a run outside the numbers, and the 49ers were constantly forced into unfavorable down-and-distances after repeated unsuccessful runs. Had Jimmy Garoppolo been more willing and capable of pushing the ball down the field, perhaps the 49ers could have punished the Rams defense for playing this way, but he is not. The Rams were willing to bet on that being the case and cashed out with a trip to the Super Bowl.

It is no secret that the approach against Cincinnati will have to look different. The Bengals are not as run-heavy as San Francisco to begin with and are far more willing to push the ball down the field. That said, it is still encouraging that Morris could so perfectly craft a game plan against one of the league's well-designed offenses and get his players to execute at such a high level. Whatever schematic necessities the Super Bowl brings, last week's win is a good sign that the Rams can figure it out.