Believe it or not, I think you can spot almost the exact moment that Jose Fernandez went from promising young pitcher to major-league ace. I’m not saying I can spot the day that his stats start getting better on a game log; that’s easy. I think I can spot the exact moment.

It was on June 1, in the fourth inning. Fernandez had danced around a few annoyances in the first four innings: a leadoff single in the first (stranded); a one-out walk in the second (caught stealing); a single in the third (stranded); and then another single in the fourth, a line drive on a 3-1 count to Lucas Duda. He had thrown 11 curveballs in the game, nine of them for balls, including the first pitch to Duda. And then this happened:

"He was keeping his heater down in the zone, throwing to both sides of the plate," Marlins catcher Jeff Mathis said. "He finally found his curveball about the fourth or fifth inning.” In three consecutive pitches, he struck out John Buck, two to find the zone with the curve and then the third to find the snap. The next inning, he threw five curves, all for strikes, including three to strike out Jordany Valdespin. And then the next inning, four curves, all of those for strikes, too. And then the next inning, four curves, all for strikes. Fernandez didn’t allow another baserunner in that game. From Buck on, he struck out seven of the 11 batters he faced. And, for the season:

  • Before John Buck: 3.56 ERA, 8.7 Ks/9, 3.6 BBs/9, .220/.300/.350 opponents line
  • After John Buck: 1.55 ERA, 10.5 Ks/9, 2.7 BBs/9, .160/.230/.210 opponents line

I think Mathis was onto something, and undersold it. He finally found his curveball around the fourth or fifth inning. Also, perhaps unrelatedly, perhaps not, he basically finally got a new personal catcher. You guys are going to kill me, but this piece isn’t about Jose Fernandez, so much as it’s about Jeff Mathis.


On a long enough timeline, the Jeff Mathis-avoidance rate for everyone drops to zero. This year is Marlins’ fans turn, and it’s going about how it always goes: frustration hearing about how great he is at calling games, frustration that he gets to play as much as he does, frustration watching him put up the 11th-worst (by OPS+) offensive season in franchise history.

To appreciate how quickly this frustration sets in, here is Marlins blogger Michael Jong describing “the Jeff Mathis experience” after Mathis’ second game with the Marlins:

But if Mathis were simply one of the worst hitters of our time, it would not mean much. I mean, no one writes full articles on Humberto Quintero or Wilson Valdez, so clearly Mathis is a special type of bad player. … Mathis is not just a legendarily poor hitter, the worst of his generation to earn playing time, but he also earned plenty of playing time. … Thus, the magically bad career of Jeff Mathis continues. It perpetuates without reason or explanation. It continues to grow despite all evidence pointing towards its end.”

I wrote plenty of those types of posts when I covered the Angels, until I quit because nothing was going to change and it got boring to channel my same dumb outrage over the Angels’ use of catcher ERA to make decisions. And nothing did change. Including Mathis’ catcher ERA, which (despite my certainty that catcher ERA was a junk stat) stayed consistently lower than those of the other catchers who shared a clubhouse with him.

Because that, Michael Jong, is what you will learn is the true Jeff Mathis experience. He will start way too many games for completely spurious reasons, he will get way too much credit for something he’ll never repeat, and you will vent until you give up, and then you will look 17 years later and notice that the son of a gun just kept repeating it, spuriously or not.

So let’s see how the Jeff Mathis experience is going in Miami. With the Marlins, he has caught 551 innings, about 44 percent of the team’s innings; Rob Brantly has caught 40 percent of the team’s innings, and Miguel Olivo and Koyie Hill have split the rest. And well wouldn’t you just know it:

  • With Mathis catching: 3.05 runs/9
  • With Brantly catching: 4.84 runs/9
  • With all non-Mathis catching: 4.84 runs/9

We know that the first offense against people who quote CERA is that these sorts of flukes happen in small samples, and that even a season or two or [as big a number as you need to adjust your argument to in order to avoid examining your own calcified beliefs] is too small a sample to smooth out all those flukes. But here’s where we stand, historically.

This is the seventh year in a row pitchers have allowed fewer runs with Mathis behind the plate than when other catchers on the same team were behind the plate.

Year Mathis R/9 Primary Alternate R/9 All Non-Mathis R/9
2007 4.26 4.66 4.74
2008 4.10 4.65 4.60
2009 4.22 5.16 5.17
2010 3.88 5.54 4.65
2011 3.58 4.04 4.17
2012 4.69 5.00 5.00
2013 3.05 4.84 4.82
Total 3.96 4.87 4.74

Want to hear something dramatically insane? In the past seven years, Jeff Mathis has caught 4,253 innings, and his primary catching partners in each season have caught 4,263 innings. Mathis has “allowed” 437 fewer runs than those teammates.

The second rebuttal to that CERA proponent is that the catcher with the lower CERA probably just caught better pitchers. For instance, Mathis has caught a disproportionately large amount of Jose Fernandez innings, and a disproportionately small amount of Wade Leblanc’s innings. This line of reasoning does a little better, because of the 10 pitchers who have faced at least 80 batters with Mathis behind the plate and at least 80 batters with another catcher behind the plate this year, five have allowed a higher OPS and five a lower OPS with Mathis. The margins are far in favor of Mathis, though, and if you average those OPSi then Mathis has “allowed” an OPS about 60 points lower. Do the same thing historically and we now have 66 pitcher-seasons, 36 of which lean Mathis’ way, for an average unweighted OPS (over more than 9,000 plate appearances) about 25 points lower.

The third rebuttal is that you don’t have time to explain it to them right now but you’ll send an email, and then just don’t ever send that email. They never follow-up, especially since they had kids.


Mathis isn’t an elite framer; he’s good, above average, worth about 72 runs from 2008 through July of 2013. The rest of catching—sequencing, managing the pitcher’s emotions, watching the batter’s feet and deducing that he’s vulnerable to some particular pitch while simultaneously watching the pitcher’s release point throughout the game and deducing that he’s likely to overthrow a slider but he’s still got good command of the two-seamer and then calculating the complex game theory involved in the situation to decide which pitch is going to get a swinging strike but not a swinging strike in the dirt because there’s a runner on third and can’t risk a wild pitch—is, frankly, too complex for us to do much about right now. But at least we can ask whether Mathis has a particular style this year. And in answering that we can conclude that, sheesh, that’s really complex, too. So we can just talk about Jose Fernandez.

If you were to look at the PITCHf/x files for Fernandez’s entire season, one small thing would jump out at you. It’s small enough that it might be nothing but a little noise, but it fits an in-a-nutshell narrative well enough that you don’t ignore it. It’s under “pitch result,” and it’s this:

  • swinging_strike_blocked: 13 with Mathis behind the plate
  • swinging_strike_blocked: four with Olivo and Brantley behind the plate

Mathis has caught about 60 percent more pitches from Fernandez than the others have, so, again, realistically we’re talking about a half-dozen extra balls in the dirt. But it makes you wonder whether Mathis is more likely to get those types of swinging strikes for a reason. And all 13 are on curveballs.

Fernandez didn’t throw to Mathis until May 16th, Mathis’ first game back from the disabled list. He then threw two starts with Brantly behind the plate, then June 1st with Mathis, then one with Brantly, and then all Mathis starts since then. And when Mathis says that Fernandez “finally found his curveball about the fourth or fifth inning,” it’s fair to wonder if what really happened is that Fernandez finally found Mathis.

  • Through May 15 (non-Mathis): 28 percent curveballs
  • May 16 (Mathis): 38 percent curveballs
  • May 17-May 31 (non-Mathis): 30 percent curveballs
  • June 1, (Mathis): 31 percent curveballs
  • June 8 (non-Mathis): 30 percent curveballs
  • June 9 on (all Mathis): 37 percent curveballs

While Brantly and Olivo called for a lot of changeups with Fernandez, Mathis almost never does. Instead, he calls for a extra curves. Those curves have generated tremendous results: one in five gets a whiff, 73 percent go for strikes (or are put in play), and of the few that are put in play are mostly outs, with a .200 BABIP and a .250 SLG on 80 batted balls.

After his July 1st start (eight shutout innings, 10 Ks, one walk, two hits, Jeff Mathis), Fernandez raved about his catcher:

"I shake him one time. The last guy I faced, because I wanted to throw one changeup at least. But once in a game? It’s incredible. Tempo-wise, he’s calling, you throw it, like I said, I shake him one time. I tell him, ‘Hey, this time I didn’t look at the videos. I didn’t do anything. I trust you. I know you’re going to do your stuff. I’m 100 percent I’m going to do what you want. He knows me really well. He knows when I like to throw the pitches.”

Indeed, Fernandez really did throw the changeup just once all game, with two outs in the eighth inning ahead in the count to Mark Kotsay. It was a ball.


What we don’t know, of course, is whether Fernandez is better because he’s throwing the curveball more or if he’s throwing the curveball more because he’s throwing the curveball better. If it’s the latter, we don’t know whether Mathis has anything to do with that, and it would be a leap to say that he does. (So far as I can tell, he didn’t go out to the mound or anything before that John Buck plate appearance, the one that we’re saying was the moment Jose Fernandez became a Hall of Famer.) There are some suggestions that Mathis calls games a bit differently than other catchers, not just with Fernandez: He has called for a higher percentage of breaking balls, and lower percentage of changeups, from the Marlins’ staff as a whole, though that might be skewed by the pitchers he has caught. He called about 25 percent more breaking balls from Toronto pitchers than the rest of the Blue Jays catchers, though, again, maybe he caught pitchers more likely to throw breaking balls. I once looked at how he and Mike Napoli handled Ervin Santana and found a bunch more sliders when Mathis caught.

Which is just to say that it’s silly to think that he would have absolutely no effect; he’s a different catcher and he catches differently.

I should note that I think this is a bunch of craziness. I spent too many of my formative years building up defenses against Jeff Mathis, and now I can’t make my brain stop thinking the way I trained it to. All these words are convincing you that Jeff Mathis might do something special not because I actually believe it, but because I believe maybe you should. If Jeff Mathis comes into your life, be patient. Observe him. Study him. Appreciate him, right or wrong. Live with Jeff Mathis once, but just leave before it makes you hard.

Thank you for reading

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Just to muddy the waters further, is Mathis doing Fernandez a disservice by basically abandoning the changeup?

The Marlins' postseason chances this year can best be described with this emoticon :( So maybe it would make more sense for the long term to mix in the changeup more often and have him get a feel for the pitch, even if that comes at the expense of his 2013 results.
Sam's work on the giant black box that is catcher defense is one of the reasons why I continue to subscribe to BP.
Last time the Angels were in the playoffs, they had Mathis.

They didn't have Pujols, Hamilton, or Wilson.

Then again, they also had Chone Figgins.

It's a weird game.
This bit about Mathis catcher ERA is one of the most interesting finds this year. How related is it to pitch framing?