Will Miguel Montero Benefit from a Three-Catcher Rotation?

When discussing correlations in the baseball world, I’ve found that you’re pretty much never going to be able to convince everyone up front that you’re not pointing out a causal relationship. If you mention a correlation—no matter the sample size or your caveats—folks will invariably laud you as having discovered the explanation for something, or (on the other hand) chastise you for junk statistics.

Still, with that preamble aside, I’m trying to say that, with this article (and so many other baseball observations we make), I’m merely pointing out something interesting I noticed. Maybe there’s something here, or maybe it’s just one of the many “things” that happens in a given baseball season, what with its unique combination of skill, human beings, physics, flukes, and randomness. I noticed something, and I’m starting a dialog.

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Miguel Montero left the Chicago Cubs’ July 11 game against the crosstown White Sox after suffering what was later deemed a sprained thumb. Although the injury opened the door for the Cubs to bring up world-beater Kyle Schwarber (and give him some on-the-job training behind the plate), it was unquestionably a blow to the Cubs’ overall performance. Coming into this season, we’d heard stories about Montero’s prowess behind the plate defensively, as a receiver, and as a commander of pitchers. Since then, as I’m sure Cubs fans will confirm from their anecdotal observations, that has played out in spades. I’ll confess I’m not the best man to describe the statistical intricacies surrounding catcher performance evaluation, but I can say that what I’ve seen of Montero tells me he’s a stud back there.

Now, I could go into the kind of small sample, purely observational anecdote here—the kind of anecdote I discussed in the preamble above—about how it seems like certain Cubs pitchers have performed considerably worse while Montero’s been out. But I won’t. I actually want to talk about something that doesn’t get a whole lot of attention when it comes to Montero: his bat.

From Opening Day until May 19, Miguel Montero was an offensive force, hitting .313/.430/.500 with a 19 percent strikeout rate and a 17 percent walk rate. That was good for a 155 wRC+. Dude was raking. After May 19, however, Montero’s production declined dramatically—from that point until his injury on July 11, Montero hit just .182/.277/.328 with a 29 percent strikeout rate, a 10.3 percent walk rate, and a mere 70 wRC+. Dude was… a good defensive catcher.

So, why did I draw an artificial line there on May 19?

Well, that’s the day Welington Castillo was traded to the Mariners, unspooling the Cubs’ previously-existing three-headed catching monster. After May 19, the job was almost exclusively Montero’s, with David Ross as his back-up, and Jon Lester’s personal catcher.

I’ll urge you not to look at what Castillo has done since that trade—especially since he was subsequently dealt to the Diamondbacks—and will instead note that the deal opened up a more traditional, near-everyday spot for Montero, who went on to play each of the next nine days (seven starts, and two games where he came in in the later innings and stayed in the rest of the way) and hit .111/.226/.259 during that stretch.

When Castillo was still around, Montero started 22 of the Cubs’ 37 games (59.4 percent). After the trade and until his injury, Montero started 35 of the Cubs’ 49 games (71.4 percent). That’s a dramatic leap for the now 32-year-old backstop. I’ll stop dancing around it and just say what I’m trying to say: I can’t help but wonder whether the ability to utilize three catchers in a rotation—both for rest and for match-up purposes—was benefitting Montero’s bat. (This is something, by the way, my colleague Matt Trueblood has written about before.) The sample, again, is small, and we’d need so much more upon which to draw any conclusions. But it’s certainly, to me, an interesting thing to note.

… and then to follow. Because, when he returns in the coming days from that thumb injury, Montero will once again likely be part of a catching trio. Schwarber isn’t going back to Iowa, and Ross isn’t going anywhere either. Presumably, Montero will still get most of the non-Lester starts behind the plate against righties (with Schwarber in left field), but he probably won’t be starting quite as much as he was after Castillo was dealt.

Could it help? Will it matter? If Montero’s numbers explode again, will we even be able to reliably say that the trio of catchers had anything to do with it? Eh. Probably not. But I’ll be watching anyway, because I like to note correlations and at least start the discussions that follow.