They believe that they know something we, out here at a distance, still haven’t discovered. The Blue Jays like Jeff Mathis, just like Mike Scioscia always liked Jeff Mathis, just like Jeff Mathis’ pitchers have always liked Jeff Mathis.
Don’t ignore this. This is data. This, in the absence of any data showing Jeff Mathis’ value, might actually be the most important data point of all. The unicorn might actually be real.
What is your preferred cold remedy? Are you confident it is the best one?
What would it take — on your next pharmacy run — to convince you to pick up an entirely different kind of medicine and go with it? Could price play a role? Sure, but you need results, and are you going to move away from what you’ve always trusted?
Spoiler alert: We’re not talking about cold medicine. Not really. We’re talking about catchers, a very unique aisle of the baseball market where front offices are indeed making this very difficult decision to move away from what they’ve known. We can be pretty sure they aren’t doing so lightly, yet from the results of the offseason thus far, you’d have to assume they know something they didn’t know before.
With new — and newly modernized — front offices taking power in Arizona and Minnesota, we expected teams to be of the same mind, just in different states and circumstances. In most ways, that has been true. But where the Twins made a predictable upgrade by luring Jason Castro, the best framer among starters on the free-agent market, the Dbacks made a move no one really saw coming, a change that had to clear that very high bar for doing an about-face in the pharmacy.
They non-tendered starting catcher Welington Castillo (and his not-unaffordable salary). If they wanted to place an emphasis on defense, then maybe it made sense. Castillo — an above average-offensive player for the position — is not good on defense, and has rated especially poorly at framing.
Still, as my colleague Henry Druschel has pointed out, Major League framing exists within a narrower band than it did even three years ago, the gap between good and bad shrinking in the wake of our wider understanding of the skill and its value. Further, the Dbacks didn’t scope out the market for a new starter that provided more financial flexibility. They had another catcher, a backup, waiting in the wings, ready to ink an admittedly very cheap two-year deal.
They chose an offensively inept part-time player over Castillo. They prioritized it.
The theory here is that the Dbacks (and other clubs) have scaled the mountain of data we are still processing. They have mapped it and they are beginning to understand the territory on a more complex, more granular and more individualized level.
Where we once had a market that balanced offensive and defensive value, then a market that balanced it differently, we now have a market in which clubs are choosing a catcher not based on his value (in the traditional sense), but on how he might inflate the effective return on other, larger investments.
Enter Jeff Mathis, baseball’s patron saint of questioning everything you know, uncommon cure for Zack Greinke’s cold.
There exists, on the Internet, a veritable trove of baseball literature plumbing the depths of Mathis’ career for signs of usefulness. It was written by Sam Miller during his time at Baseball Prospectus, and you should read it. We are not here to retread that path, but instead to advance a theory as to why Mathis was a coveted commodity, to at least one team, in the year of our lord 2016, in our possibly morphing catcher market.
My colleagues at AZ Snake Pit have already explained some of Mathis’ framing appeal, advancing the idea that Mathis may be paired with the Dbacks’ $206.5-million man, Zack Greinke — whose career has already illustrated some of framing’s potential effects.
In early 2015, he said, “I believe that some catchers are better at framing pitches. But I’m not a believer that it’s as valuable as it’s being made out to be. It’s part of a catcher’s skill set. It’s not the most important part.” This opinion may have mellowed, after he went from personal catcher A.J. Ellis (one of the worst framers) to (Yasmani) Grandal, who caught all bar 8 starts in Greinke’s epic campaign that year. There’s certainly a case throwing to Beef may have been part of Zack’s issues here, and I wouldn’t be surprised to see Mathis become Greinke’s regular battery mate.
Mathis rated among the top framers on a per-pitch basis last season, according to Baseball Prospectus. He was behind the stellar Grandal, but not by much (in previous seasons, Mathis has been simply above average).
I’m guessing the Dbacks front office has looked at this from another angle, though.
In our exuberance to separate good framers from bad, we haven’t taken as much time to parse the intricacies of the skill, and that extra step may explain the targeting of Mathis, who appears especially comfortable calling for low pitches and turning them into strikes.
Looking to Baseball Savant for ways in which Mathis distinguished himself, this is the most notable: Mathis and Castillo received a greater percentage of pitches in the areas outside the bottom half of the zone than any other catchers (min. 5,000 pitches received). Mathis, notably, received a significantly larger portion of those pitches than the Marlins’ primary catcher, J.T. Realmuto. Those phenomena extend back for several seasons — as Mathis, Francisco Cervelli, former Dbacks catcher Miguel Montero, David Ross and several others continuously paced the league in low pitches received.
A Dbacks catcher tends to appear. And he tends to fall short of Mathis in the called-strike department. In 2016, Mathis converted 16.4 percent of pitches taken in those zones into called strikes, compared to Castillo’s 13.6 percent. If you’re a visual person, their plots of called strikes looked like this.
With those rates, you’d expect Mathis to secure 411 called strikes for every 2,500 pitches taken in those zones while Castillo gets 339 calls.
To pile on, here are the charts of Mathis’ and Castillo’s 2016 performance on pitches taken in the bottom third of the actual strike zone.
I’ll pause to remind you that these numbers don't reflect solely their abilities. Some of those pitches are beyond help, others are relatively easy frame-ups, etc. It’s very difficult to decipher which is which, and best left to the comprehensive work being done at BP and elsewhere. But the difference seems to square with the information available to us: Mathis is a better framer, and perhaps decidedly so on low pitches.
Anyway, this isn’t intended to be the most advanced analysis, but instead a dog-eared data point, a breadcrumb.
That's because if you consult Baseball Savant once more, you’ll find a very big incentive for the Dbacks to pursue a player who excels at converting those specific pitches into strikes. The club threw more pitches in the areas outside the lower part of the zone than any other team in 2016 — possibly an attempt to stem the flood of home runs at Chase Field.
And among players who threw 2,500+ pitches, Greinke threw the third-highest percentage of his pitches in those areas, while Patrick Corbin — a promising pitcher whose rebound from a rocky 2016 could be key to the club’s 2017 prosperity — led all hurlers.
For reference, Greinke threw almost precisely the same number of pitches in those zones as Max Scherzer, a pitcher who overall threw more than 1,000 additional pitches across 70 additional innings.
#Dbacks mgr Torey Lovullo says plan is for Jeff Mathis to catch about 60 games.
— Steve Gilbert (@SteveGilbertMLB) December 6, 2025
With those data points and the stated usage goal for Mathis in mind, I’m going to go out on a limb and predict that you’ll be seeing him behind the plate as the primary catcher for Greinke and Corbin.
The duo also shared prime real estate in another category: Among pitchers with 120+ IP, Greinke and Corbin were 13th and sixth, respectively, in terms of throwing inside the strike zone the least. These are pitchers who want to live outside the zone. Greinke’s historically good 2015 came along with a career-low 39.9 percent zone rate.
There is likely even deeper reasoning behind the Dbacks’ acquisition of Mathis, but these highlighted facts alone could convince you that the change at catcher might have real, positive implications for Greinke.
And it leads to the questions that may drive future catcher markets: How much of a difference can a catcher make when it comes to a pitcher’s performance? Can that value be accurately attributed to the catcher?
We may witness several high-profile tests of the first question in 2017. Greinke will have the chance to bounce back by emulating 2015’s wildly successful dance around the edges of the plate. And Cubs lefty Jon Lester will face a very different, but no less relevant, challenge in forging on without personal catcher and running-game-suppressor Ross.
The second question is more difficult. It’s not clear that framing, in general, has been properly valued in terms of compensating catchers. We may be learning about the position too quickly, at the moment, for any breakthrough to translate into dollars — every newly discovered talent washed away by another eureka moment as clubs send comparatively expensive catchers packing in favor of other backstops, unknowingly equipped with a skill that makes them a bargain at only $2 million per year.
. . .
Zach Crizer is a contributor at Beyond the Box Score. You can follow him on Twitter at @zcrizer.
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