San Francisco 49ers 2021 Team Study

Part 30 of my 32-part series breaking down every team’s performance in 2021. Check out part 29 here: Los Angeles Rams. Part 31 now available: Seattle Seahawks.


Eff. RatingAdj. RatingRank
Offensive Eff. Rating (red and gold) v. opponent average allowed (grey).
Pass EPARush EPAAdj. Pass Rate

To beat the NFL’s best teams, you must pass the ball efficiently. If you’ve been following me for a while, you’ve seen me hammer this point. I bring it up every year when the playoffs arrive. But the important caveat is that you don’t necessarily need to pass a lot. You can win with a run-heavy approach as long as your run game sets up an efficient passing attack, preferably with explosive plays. In fact, without an elite quarterback, this is the optimal approach.

The 49ers found success in 2021 once again with the 4th-lowest adjusted pass rate. Shanahan’s run scheme famously creates open space for playmakers by using misdirection and setting up optimal play-action opportunities. It’s an offense focused on yards after the catch. But it’s a mistake to say the quarterback has nothing to do with it. Garoppolo has missed some throws in his career, but he possesses underrated anticipation skills and delivered the NFL’s 2nd-highest on-target percentage on his throws in 2021. He’s simply not good enough to elevate a team around him, but in the right circumstances he can give you what you need.

The 49ers have lived off explosive plays for years now. They aren’t typically throwing deep bombs for 80-yard touchdowns. But their ability to create chunk plays – the 25 yard catch-and-run to Kittle or the Deebo Samuel misdirection run – makes them extremely successful on a drive-by-drive basis. Their run game lost explosiveness without Mostert, but Deebo’s emergence as a weapon in the run game offset this loss. The versatility of this offense made it extremely difficult to defend with typical defensive aggressiveness. 

Teams that relied on the blitz to exert pressure were frequently stymied by this offense. The 49ers thrived when they could create open space, and when defenders moved out of coverage into the backfield it just created more space. Garoppolo was smart enough and quick enough to capitalize. Chart A shows the 49ers’ Adjusted Effectiveness against each opponent ranked by its blitz rate on the season:

Chart A

Offensive Adjusted Rating per game against each opponent ranked by its season-long blitz rate.

This chart demonstrates that this offense’s relatively poor performances all occurred against teams that did not blitz. Blitz-heavy defenses rely on making big plays but the 49ers did not give up a lot of big plays because they protected Garoppolo well and did not put him in a lot of dicey situations. They also performed relatively well against teams that had a high conversion rate of sacks to pressures. This methodical offense prevented sacks and did not lose its edge when the field shortened. They finished with the 2nd-highest red zone conversion rate in the NFL because they controlled the short area so well.

The 49ers have had sustained offensive success without an elite quarterback. This is rare. Trey Lance looked quite bad in his limited opportunities as a rookie, but this is still the ideal spot for a raw quarterback prospect. Over the years we have seen some of the best all-time quarterbacks (such as Aaron Rodgers and Patrick Mahomes) emerge on talented teams after learning from the bench as a rookie. This obviously does not guarantee success for Lance, but I believe circumstances play a massive role in a young quarterback’s development. With Garoppolo still on the roster, the 49ers will only go to Lance if he is ready to win now. The roster is too good to squander a year away.

If Lance can do the little things well, he brings an upside to this offense that makes the team a legitimate Super Bowl contender. And if he is the next elite quarterback, the 49ers could be the outright Super Bowl favorites. But if he struggles with the easy throws or cannot process defenses effectively, it creates tension on the roster that could be difficult to deal with. The range of outcomes is wide, but even with Garoppolo, this is a solid offense when healthy. Lance just gives them a potential upside we haven’t seen yet.


Eff. RatingAdj. RatingRank
Defensive Eff. Rating (red and gold) v. opponent average allowed (grey).
Pass EPARush EPABlitz RatePressure Rate

The 49ers defense imposed its will up front, led by superstar Nick Bosa with help from a strong rotation of linemen (including Arik Armstead) and linebackers (including Fred Warner). It was really tough to run against this front, as they plugged gaps effectively and tackled aggressively. It was also really tough to escape pressure with how quick Bosa came off the edge. And if you double-teamed Bosa, the rest of the line was strong enough to get penetration.

Of course, they had to win up front because their secondary was a liability. If they didn’t disrupt the pocket it would have been too easy for top quarterbacks to capitalize on mistakes in coverage. The problems in the secondary were especially egregious given that the 49ers did not blitz frequently. The upside of not blitzing should be that you excel in coverage. The 49ers still struggled in coverage, leading to a bottom-10 defense against the pass in terms of EPA/play.

Their biggest problem was giving up first downs with penalties. On the season, they gave up 37 first downs by penalty, including 15 on third down. Both numbers were the highest in the NFL. The defense actually had a decent rate of success, but these key results in high-leverage situations hurt them badly. No game sticks out more in this regard than their 30-18 loss to the Colts in which Wentz got three big first downs on defensive pass interference calls that totaled 97 yards. When the cornerbacks are struggling, you can succeed by chucking the ball downfield and hoping for a catch or a call.   

Nothing was easy against this defense. Solid tackling limited yards after the catch and explosive plays were not easy. Good pressure made it more difficult for teams to abuse the weakness in the secondary. So the teams that tended to outperform against the 49ers were more inconsistent, aggressive offenses. Some really good quarterbacks struggled with the 49ers because they couldn’t simply impose their will like they were used to.

Now, the 49ers have addressed their biggest weakness by picking up Charvarius Ward from the Chiefs. This could be a huge material addition, because if they make fewer mistakes downfield they could be an elite defense. They will need to stay healthy of course, but they now possess the type of talent and leadership at every level that is the hallmark of an elite defense.

Key Takeaways

When to bet on the 49ers: The 49ers come to play against really good competition. Good coaching and team chemistry give them an edge, and really good pocket quarterbacks that routinely abuse the blitz struggle to find their edge against this defense. As long as they project to win the line battles, this is a bet-on team.

When to fade the 49ers: Because the 49ers are such a strong team, they can get inflated spreads at times. I don’t love going against a team like this, but more wild and erratic quarterbacks – like Carson Wentz – can have relatively good games because they take chances.

Evaluating the off-season: Picking up Charvarius Ward was huge for the defense. But the big question remains at quarterback. Can they win a Super Bowl with Jimmy Garoppolo? They certainly came close twice in three years. If they move on to Trey Lance there is much more downside, but potential upside as well.

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