Jimmy Garoppolo matters, he matters a lot

However you slice it, Garoppolo has been a major driver of 49ers success

It’s been a whirlwind off- and regular season at the quarterback position for the San Francisco 49ers. Despite taking the team to the Super Bowl two years prior, and the Divisional Round last season, Jimmy Garoppolo was out in 2022, and Trey Lance, the quarterback the 49ers mortgaged their future for was in. Offseason surgery muddled the trade market for Garoppolo, and, in the end, all parties decided it was best for him to return to the 49ers as their backup.

Things didn’t die down for the 49ers once play started: Trey Lance was seriously injured in the first quarter of Week 2 and declared out for the season, the 49ers mortgaged even more future draft capital for dual-threat superstar Christian McCaffrey, the team emerged as a serious Super Bowl contender with strong play, and then Garoppolo caught the injury bug last week. There’s some uncertainty whether Jimmy will be back late for a potential 49ers’ playoff run or not at all. Either way, Brock Purdy, Mr. Irrelavant, will be the 49ers quarterback for the foreseeable future.

The loss of a starting quarterback would impale the Super Bowl chances for most teams, but this 49ers squad has some of the best surroundings outside of the quarterback. The team’s defense has posted second best efficiency against this season, and the team includes a Pro-Bowl roster of skill position players, including the aforementioned McCaffrey, Deebo Samuel, George Kittle and Brandon Aiyuk (I guess Kyle Juszczyk warrants mentioning as a six-time Pro Bowler).

The verdict of the all-knowing, bloodless markets on the matteringness (not a word) of Garoppolo has been noticeable, but not especially significant. The 49ers Super Bowl odds moved from roughly +700 pre-Garoppolo injury to +1200, which translates to implied probabilities from 12.5% to 7.7%. A 40% drop in Super Bowl odds isn’t nothing, but the 49ers chances to win it all are still higher on betting markets than the Bengals and Dolphins. Part of that is their easier path in the NFC, part is a lack of belief that the 49ers need Garoppolo to win it all.

Looking at short-term odds, this Week 14 matchup between the 49ers and Bucs went from the 49ers as 6-6.5 point favorites to 3.5. The moneyline moved from around -285 to -190, or the implied probability of a 49ers win from 74% to 65.5%. A move of 8.5% in win probability for the loss of a starting quarterback is relatively small, likely smaller than it would be for the loss of any quarterback among other top contenders for the title.

The larger football media world agrees with the markets, and might even see Garoppolo have less matteringness to the 49ers. It’s harder to nail down what “approximating” someone else means exactly in terms of matching quarterback value, but many are optimistic Purdy will approximate Garoppolo down the stretch. In a small sample, film watchers liked what they saw from Purdy, so maybe the sharp play is to bet the 49ers won’t miss Garoppolo on the march to Glendale.

The numbers don’t care about our feelings

I get the idea that Garoppolo doesn’t look, or better yet “feel”, like he matters much. Listen, even as a diehard Jimmy truther I don’t particularly enjoy watching him play quarterback, outside of him giving YAC monsters like Deebo Samuel a outsized chance to shine. But I also know that my feelings aren’t going to be as predictive and insightful as some kind of analysis that’s grounded in facts and concrete terms of value. That’s why I prefer to turn to the data.

The anti-#QBWinz crowd has snark to return in the face of the oft cited 43-18 record for the 49ers since 2017 with Garoppolo taking the majority of quarterback snaps versus 8-30 with anyone else. Should we then assume Garoppolo, by himself, would turn a team that wins 20% of its games to one that wins 70%? Of course not. At the same time, the ample noise in that sample doesn’t mean we simply dismiss any chance of signal.

The 49ers other starting quarterbacks since 2017 have largely played with lesser defenses and weaker offensive talent than Garoppolo. The 49ers defense ranked second in EPA per play against when the 49ers went 14-2 and all the way to Super Bowl in 2019, but were 26th the previous year when the team went 4-12 and most of the quarterback snaps went to Nick Mullens and C.J. Beathard. Garoppolo has played the majority of his snaps with either Deebo Samuel or George Kittle on the field, whereas Deebo missed most of the 2020 season when backups had to take over for Jimmy. If you combine this context with your feelings that Garoppolo isn’t that good, it can appear logical that he isn’t going to be severely missed. But good analysis requires us to go a step or two further.

First, we can isolate offensive efficiency with stats like EPA per play, so the team defensive strength doesn’t have to be considered to answer how quarterbacks affect the game. Second, the excellent participation data available as part of the nflverse allows us to isolate of the results for quarterbacks with certain players on and off the field. If the argument is that Garoppolo benefited greatly by having Samuel and Kittle on the field when others didn’t, we can pull out the numbers for different combinations of talent and see the results.

I looked specifically at plays with Deebo Samuel and George Kittle both on the field, only one on the field, and both not on the field for the three 49ers quarterbacks with enough sample since 2017 to make a meaningful comparison. You will notice that Jimmy has benefited from a higher proportion of plays with those two receivers. Both were on the field for roughly half of his 49er dropbacks, and the vast majority had at least one playing. At the same time, Garoppolo has played material snaps with neither on the field, and his efficiency in those circumstances was even higher. It isn’t the biggest sample at 226 plays, but half-a-season’s worth can’t be dismissed.

Garoppolo has a shocking consistency of play, no matter the surroundings, for someone with the reputation of especially dependent on others to succeed. Even his efficiency in 137 dropbacks with the Patriots as was right around what it was after joining Shanahan and 49ers (0.14 EPA per play). Like all quarterbacks, Garoppolo isn’t immune to surroundings and coaching, but data doesn’t show he’s a product of them.

When everyone knows you’re passing the ball

Often the usage of playaction and stacked boxes to stop the run are associated with quarterbacks in the Shanahan system seeing success they wouldn’t otherwise. Basically, coaches are pushing the easy button for their quarterbacks, leading to a general boost in passing efficiency. On the other hand, offenses that rely on quarterbacks to make plays under defense scrutiny don’t get as high a proportion of plays for the quarterback to to generate high efficiency.

Playaction spilts would one way to examine this further, but even better, in my opinion, are third down splits. A lot is made of play tipping of pass or run based on formation, personnel or idiosyncratic tendencies of offensive players, but the true tip is down and distance, especially third down. Teams pass the ball the overwhelming majority of the time on third down, averaging a nearly 70% pass rate on third & 2, with the rate exceeding 80% on third & 3.

You can’t scheme or playaction your way out of fooling the defense into thinking “run” on third down, so it’s the best approximation of how quarterback play is affected by the defense being focused on passing. There aren’t the same easy buttons at an offenses disposal in these situations.

Jimmy also comes also to play on third down. His EPA per play for these pass-obvious downs is even better than for early downs, whereas other 49ers quarterbacks have fallen without the tricks that their coach can employ passing in run-friendly early downs.

If you look at the list of the best NFL quarterbacks in third down efficiency, it reads exactly as those who film watchers would identify as having system-proof ability …… and also Jimmy Garoppolo. For passers with at least 200 dropbacks since 2017, the top-five in third down efficiency are Patrick Mahomes, Jimmy Garoppolo, Andrew Luck, Justin Herbert and Aaron Rodgers.

Other “system” quarterbacks, who are often thrown in the same bucket with Garoppolo, do show some dependence on early down tricks for success. During the same period, Drew Brees’ early down efficiency ranked first, but on third downs he ranked 21st (of 55). Ryan Tannehill ranked 6th and 36th, respectively. Kirk Cousins’ EPA per play fell from 0.10 to flat going from early to third downs.

What does it all mean

We can’t be certain of anything, but the 49ers losing a quarterback who has displayed steady, efficient performance under almost all circumstances, should be a significant loss. It appears that markets, while recognizing Jimmy’s value more than many most football analysts, aren’t pessimistic enough about the 49ers chances without Garoppolo. Brock Purdy might be a better than expected talent for a seventh round pick, but our expectations should be low. That said, 49ers have the defense to make noise the rest of the the season, and we’ve seen teams with middling-to-bad quarterback play win it all before.

The point of this analysis wasn’t primarily to bury the Garoppolo-less 49ers and predict their demise as much as show that many of the arguments against Jimmy’s value (the scheme, the weapons, throwing on run downs, the defense) don’t show up in the evidence. It’s not enough go on feelings when seeking understanding, especially when the data is sitting right there waiting to be explored.

P.S. Put some respect on Jimmy’s name, people!!