The 49ers entered 2020 with high hopes following a tough Super Bowl loss to the Chiefs. But injuries on both sides of the ball quickly derailed their season. The offense ranked 18th due to major skill player injuries. Kittle, Mostert, and Deebo Samuel all missed over half the season. Starting quarterback Garoppolo also missed chunks of time and rookie receiver Aiyuk came into the season injured and missed several games on the Covid list. Even their second-best running back (Jeff Wilson) missed time.
They ran the same offense that led them to success in 2019. Shanahan’s famous system involves a zone run blocking scheme where the linemen move together and try to create one hole for the running back to break through. When the line moves cohesively this puts less pressure on individual linemen winning every battle. If the running back can find the hole and hit it with an effective cut, there is a good chance for an explosive run. It also forces huge commitment by the defense to follow the blocks and close every gap, which opens up play action. In addition, the blocking scheme creates one-way motion that leads to effective reverses to wide receivers who can catch the defense off guard, heading in the wrong direction. Structurally, the 2020 offense mirrored the offense they implemented in 2019.
SF Offensive Structure, 2019 to 2020
|Stat||2019||2020||2019 Rank||2020 Rank|
|YAC per comp.||5.9||5.4||1st||4th|
|Bad Throw %||13.6%||15.9%||3rd||10th|
|Play Action Pass Yds||1,473||1,344||3rd||5th|
As in 2019, the 49ers did not throw deep but instead focused on getting their talented weapons the ball for yards after the catch opportunities. They limited bad throws and took advantage of play action. Shanahan tried to work through all the injuries without giving up on his system. But ultimately, it just was not as effective in several key metrics.
SF Offensive Production, 2019 to 2020
|Stat||2019||2020||2019 Rank||2020 Rank|
|Explosive Run Rate||13%||11%||6th||21st|
|Explosive Pass Rate||12%||9%||1st||11th|
|YPC on WR Runs||11.6||N/A||7.4||N/A|
A passing game built around high-percentage throws will not succeed when completing only 65.1% of passes. And committing 31 turnovers – the 2nd most in the entire NFL – is unforgivable in a system designed to limit exposure to negative plays. Explosive plays were down and they were less effective on wide receiver runs. Kittle’s pass catching and blocking makes a huge difference for this offense and his injuries had a major impact. In addition, they needed at least one of Samuel or Aiyuk to play the “electric WR” role. Kendrick Bourne and the other receivers lacked the skill set that these two provide in both the run game and the pass game.
As a result, the 49ers offense was far more effective when both Kittle and at least one of Samuel or Aiyuk played.
This chart splits the 49ers’ offensive Adjusted Rating into games where Kittle and at least one of Samuel or Aiyuk played (red line) and games where either Kittle or both receivers missed (gold line). In 7 of their 8 games in which they played below their season average, either Kittle or both Aiyuk and Samuel were absent. And in 5 of their 8 above-average games, they played with Kittle and at least one of the two receivers.
San Francisco’s lack of explosive plays hurt them offensively because their system is designed to capitalize on speed. This didn’t happen. But San Francisco’s 31 turnovers were arguably an even bigger problem. Considering they implemented a steady amount of short, high-percentage passes, this number was devastating. Only two other NFL teams had more than 27 turnovers, and they both employed a much more aggressive and risky scheme.
NFL Teams with 28+ Turnovers in 2020
|Team||Turnovers||ADOT||Comp. %||Bad Throw %|
Turnovers tend to increase when you throw downfield aggressively and make a lot of bad throws. You take the risk for the benefit of making splash plays in the deep passing game. But the 49ers did not throw downfield, so their 31 turnovers came without the benefit of a downfield passing game.
The run game was also much less effective in 2020, particularly when both Mostert and Wilson were hurt. Mostert averaged 5.0 yards per carry and Wilson averaged 4.8. These numbers show what backs are capable of in this system. But McKinnon, Hasty, and Coleman each ran for fewer than 4 yards per carry. When they were forced into the starting role, the offense was noticeably weaker.
Although injuries impacted game-to-game performance, you can nevertheless see that the 49ers’ offensive archetype outperformed against teams that relied on good secondary play. When you don’t overly rely on receivers winning traditional routes against cornerbacks, defensive back strength is less relevant to your success.
This chart shows the 49ers’ offensive Adjusted Rating in games ranked by each opponent’s average depth of target allowed on defense. Teams with good secondary play, like the Rams, Bills, and Giants, limited deep passing well and allowed some of San Francisco’s best performances. By contrast, several of the 49ers’ worst performances came against teams more susceptible to deep passing. The 49ers lacked the scheme and personnel to take advantage.
I anticipate the 49ers will stick with the system in 2021 and look to bounce back with key players staying healthy. If they do, they should return to 2019 form, particularly if Brandon Aiyuk can emerge in his sophomore season and if they improve their quarterback play in the draft. With the number 3 pick, if they target a player who can throw accurately and avoid turnovers they will maximize immediate success in this offense.
The 49ers defense was also ravaged by injury in 2020, perhaps even more so than the offense. Nick Bosa, Dee Ford, and Richard Sherman all missed most of the season. In an NFL built around passing, it’s impressive that San Francisco’s defense finished 5th on the season without two top pass rushers and an elite corner. They suffered other injuries as well. According to Football Outsiders, the 49ers suffered more meaningful injuries than any team in the past 20 years except the 2016 Bears.
But in the face of these injuries they played their game defensively. They stayed disciplined and stuck to their assignments. They tried to pressure the quarterback, dialing up more blitzes without their star edge rushers. Overall, they played well on a yardage basis, limiting opposing teams to 5.0 yards per play, which was good for 5th in the NFL. They also allowed just 5.9 net yards per pass attempt, good for 7th in the NFL.
But they just didn’t get enough negative plays. After forcing 27 turnovers in 2019 they forced only 20 turnovers in 2020. After recording 48 sacks in 2019 they recorded only 30 sacks in 2020. If you limit big plays and get pressure but do not turn that into sacks and turnovers, your defense will lose a lot of its effectiveness.
They did face some of the league’s most mobile quarterbacks. On the season, half of their games came against quarterbacks with 400 or more rushing yards. But that didn’t mean that the 49ers performed worse in these games.
49ers Defense v. Mobile QBs
|Games||Avg. Adj. Rating|
|v. QB with 400+ rush yds||8||+0.42|
|v. QB with 399- rush yds||8||+0.39|
San Francisco tried to make every drive tough for opposing offenses despite forcing relatively few negative plays. This meant that teams who implemented a slow, methodical march down the field struggled against them when compared to teams with a more aggressive approach. To beat the 49ers, you were better off throwing deep and going for big plays than trying to eke out 4-5 yards a play.
This chart tracks the 49ers’ defensive Adjusted Rating ranking each opponent by average depth of target on the season. Successful downfield passing teams like BUF (-1.06), SEA (-0.51), and GB (-0.16) caused the 49ers the most problems. But teams that either didn’t throw deep like WAS (+1.30), NO (+1.23), or LAR (+1.12) or threw deep but poorly like PHI (+0.54) and NYJ (+0.48) presented good matchups for San Francisco. Note that they had a poor game against MIA (-0.88), who played that game with Fitzpatrick, a much more aggressive and successful downfield passer than Tua in 2020.
Getting Bosa and Sherman back will bolster this defense. If Ford returns, or if they bolster their pass ruth through free agency or the draft, they could return to 2019 form. But coach Robert Saleh has also moved on, so it will be interesting to see how closely they stick to the system. They have the talent to be an elite defense again but they will need to force more negative plays.
Putting it All Together
- San Francisco is underrated heading into the offseason. In addition to the crippling injuries – which I think every analyst appropriately credits – the 49ers lost four games that they should have won according to my Ratings. Their inordinate amount of turnovers, particularly lost fumbles, skewed their results to the downside. Anticipate positive regression in addition to benefitting from a healthier squad.
- Specifically, expect explosive plays to increase and turnovers to decrease in 2021 given their style of play.
- Have confidence in the 49ers offense against teams who excel at defending aggressive passing offenses with stud cornerbacks. These defensive archetypes match up poorly against their offensive system.
- Keep an eye out for defensive scheme in the wake of Saleh’s departure. If they remain consistent and stay healthy, anticipate more negative plays and overall improvement.
- Increase confidence in San Francisco’s defense against low-ADOT dink-and-dunk offenses, but be more cautious against teams who can successfully throw downfield.
Fantasy and Player Prop Takeaways
- In this offense, running backs are pretty much plug-and-play options. Given Mostert’s injury history, back-up 49ers running backs make excellent bench stashes in fantasy. And Mostert may provide value if he stays healthy, because the 49ers’ blocking scheme perfectly complements his running style.
- Kittle is an absolute monster at tight end. But given the 49ers’ non-traditional offensive style, both Samuel and Aiyuk will likely have limited upside in terms of fantasy production. The 49ers are at their best offensively when running the ball. They make interesting depth options but should not be centerpieces of a fantasy squad.
- Avoid conservative offenses against San Francisco. Evaluate the defensive scheme early on to determine if any sharp prop betting angles emerge.
Application: SharpClarke Bet of the Year
In Week 7, the 49ers were finally getting healthy on offense. Kittle, Aiyuk, Garoppolo, and Samuel were all ready to go against a New England team that just did not look good. The 49ers were shockingly 2 point underdogs in a matchup I favored them to win comfortably. Their defense matched up perfectly against a team that didn’t threaten deep in the passing game and their offense was set with all their meaningful weapons (outside of Mostert). The line partly reflected how underrated the 49ers were and partly that the public had not yet caught on to how bad the Patriots were. I liked both angles and bet SF +2. They won comfortably, 33-6.