Catcher Symbiosis
How well does a catcher work with their pitching staff? How should we measure that? Can we even measure it?
Catcher Value and Framing
Which player was more valuable in 2014 on an fWAR per 500 PA scale: Mike Trout or Rene Rivera? If you said Rivera, you’d be correct; his 7.93 fWAR/500 PA actually led all position players that year (min. 250 PA). He played in just 103 games to accumulate a fantastic 5.22 fWAR, and he maintained a respectable-although-not-too-impressive 113 wRC+. So how did Rivera manage to have one of the most valuable seasons of any position player over the last 15 years despite being just a decent hitter? He was excellent defensively - especially in his ability to steal strikes via framing.
Catcher framing is something that we have been able to measure and quantify over the last decade thanks to advances in baseball technology. But even before that, teams have had their own internal methods of evaluating catcher framing. Other advanced defensive metrics related to catching have made their way into the public sphere. These measurements give us some insight into just how valuable catchers can be to their teams, and the vast majority of a catcher’s job involves their defensive duties.
Growing-up a Rays fan, I never expected much offensively from the catchers on the roster. The rationale for the team giving valuable playing time to guys like Rivera, Jose Molina, and Gregg Zaun is pretty clear in hindsight. Rays fans are well aware of Ben Zobrist’s 2009 season when he amassed a Trout-esque 8.70 fWAR (7.26 fWAR/500 PA) thanks to his versatility, defense, and a whopping 152 wRC+. His fWAR/500 PA led all position players that year, just beating a pair of catchers - Joe Mauer (6.93) and Gregg Zaun (6.16). But my personal World Series was 2012 Jose Molina. Below is a list of the top ten position players by fWAR/500 PA for the 2012 season (min 250 PA).
At first glance, you might notice six catchers here. You might also notice Jose Molina’s abysmal 81 wRC+ and Ryan Hanigan’s (who the Rays grabbed a few seasons later in 2014) 88. Catcher defense, especially framing, is extremely valuable. Four of the top ten seasons by fWAR/500 PA since 2008 came from catchers.
Proactive Framing
I believe that framing might be the single largest component when determining a catcher’s overall value. There are usually a couple hundred pitches thrown in an average MLB game. Not all of them are thrown around the edges of the zone where framing occurs, but there are far more opportunities to frame a pitch for a strike than any other action a catcher will take in a game. This is not to say blocking and throwing are not important, but framing might be the most important.
Framing also gives us some insight as to how much a catcher is “on the same page” as the pitcher throwing the ball to them. Being proactive in framing rather than reactive helps catchers steal even more strikes. A few factors go into what I would consider proactive framing.
Tempo
In this context, tempo would refer to the speed and rhythm in which a catcher and pitcher execute their game plan. This doesn’t necessarily mean they need to work fast, but a catcher and pitcher who are in-sync would work relatively quickly, at a speed where the pitcher feels most comfortable, and that speed would remain relatively consistent from pitch to pitch. Catchers who work well with their staff would be able to anticipate the pitch and location at which the pitcher wants to throw it because both players would be in-tuned with the team pitching philosophy in addition to the catcher knowing that pitcher like the back of his hand. A catcher being especially aware of how to attack a specific hitter while working with a specific pitcher would be even more adept at maintaining a good tempo.
While we do have public access via Baseball Savant to pitcher tempo, we currently do not have any data on catcher tempo unfortunately. This is something that would help provide insight into catcher “symbiosis” (I’m assigning my own denotation here; symbiosis refers to how well a catcher works with their staff). I believe the catchers with relatively quick tempos would predominantly be the ones who work the best with their pitchers and probably have higher framing strike rates as a result.
K/BB Rate
Strikeout to walk rate is absolutely more of a pitcher statistic, but I believe it still has some value in highlighting catcher symbiosis. Pitchers who feel more comfortable with their catchers can attack the strike zone, and the catchers are well aware of how their pitchers want to attack the zone. Catchers can help their pitchers avoid walks by framing well and adhering to team pitching philosophy as well as individual plans for attacking hitters - also leading to more strikeouts. K/BB can be influenced by a catcher’s framing ability, but it can also be influenced by how well a catcher calls pitches. Game calling and framing strike rate combine to show catcher symbiosis, and K/BB rate gives us some imperfect insight as to how well a catcher works with their pitchers.
Time Spent in an Organization
Like K/BB rate, this is not the ultimate way to measure catcher symbiosis, but I still believe it’s a piece of the puzzle. The concept is simple, a catcher who has spent more time with their organization would most likely be more skilled at executing team pitching philosophy. This would not just be evident in framing strike rate, but K/BB as well - and even tempo if we had public access to it. A catcher who is skilled at framing could still find success bouncing around from team to team, but looking at all the factors mentioned above from a more holistic view would help paint a picture as to which catchers are the best at working with their pitchers
Putting the Puzzle Together
While we don’t have public access to all the necessary data and their are things individual organizations do to evaluate how well catchers work with pitchers, we can still work with what we have to do some analysis. Below is a graph comparing framing strike rate (x axis), K/BB rate (y axis), and the time a catcher spent in their most recent organization (bubble size). I created this using data from Baseball Reference and Baseball Savant. For a catcher to be qualified in this sample, they needed to receive at least 250 pitches in both 2022 and 2023 for the same team. I chose these parameters in order to get a framing strike rate in a meaningful sample, and I wanted to only include catchers who had more than one season of continuity working with mostly the same pitching staff to help control for catchers who might be trying to learn a new staff or pitching philosophy.
I wouldn’t say it’s statistically significant, but most of the catchers with more time spent in their current organizations as of the 2023 season were better than average at framing and had better than average K/BB rates with the exception of a few outliers.
We can also see there is some sort of relationship between both K/BB and time spent in an organization, and framing strike rate and time spent in an organization.
Next Steps, ABS, and More Questions
It’s apparent that there’s still a lot of work to do in measuring catcher symbiosis. It might be years before we have enough public data to determine which catchers are the best at working with their pitchers, but I believe we can start putting the puzzle together now. I plan to continue looking for ways to measure catcher symbiosis, and I will update the data I have here following the conclusion of the 2024 season. I will also look into both K/BB rate and framing strike rate among catchers that have changed organizations between seasons and compare that data with catchers who stayed with their organizations.
Another side project I’m looking forward to is how the league implementing automated balls and strikes (ABS; aka robot umpires) could impact catcher value. Framing (which I still believe is the carrying tool for catcher value) would become less important, but I don’t think ABS would make catcher symbiosis less important. In fact, implementing ABS might help accentuate a catcher’s ability to call a game and work with their staff by controlling for catchers who are good at framing no matter who they are working with.
Overall, analyzing catcher symbiosis has created more questions than answers. It’s exciting to think about thie next frontier in determining catcher value through this lens, and I personally enjoy exercises like this where looking at the data - both anecdotally and the things we can quantify - forces us to try to piece things together rather than providing a direct answer.
Interesting article!
Regarding catchers who have spent more time in orgs and the symbiosis that emerges from that time, what do you think about orgs like TEX and MIL which integrate newer Cs well.
MIL - Narvaez and Contreras
TEX - Heim and John Hicks (Trevino was theirs for a while)
Incredible insight. 🤯