I want to start off by saying a few things about this little experiment with a few disclaimers, and an explanation, because (spoilers!) my theory turns out to be at best un-provable and at worst (and most likely) junk*. But sometimes it’s good to look at the things that don’t work out, and anyway, someone might actually be able to make use of this data at some point.
I got the idea for this post when AK and I went to see the Rattlers play a few weeks ago. At that game Jorge Lopez threw an absolute gem and, I thought, 3rd string catcher Brent Dean caught a great game. He frequently brought low balls back up into the strike zone and controlled the running game when guys did get on.
If you follow prospects you probably know of Clint Coulter. Coulter is believed to have some of the highest upside in the organization, and the Brewers hope to turn Coulter into a catcher in order to make the most of that upside. Coulter started the year in Appleton but has since been sent back to Helena for some more seasoning.
Jorge Lopez is a decent prospect in his own right and is considered to be having a breakout season. Since I saw Dean basically make Lopez better, I thought it might be worth looking into whether Coulter made him worse. If Lopez is having a mid-season breakout, perhaps it coincides with better guidance behind the plate.
FIP by Catcher:
Parker Berberet – 4.356
Brent Dean – 6.5
Clint Coulter – 3.857
I’m using FIP just because minor league defense is such garbage I figured we’d stick to what he has some control over. If you just look at FIP Coulter looks to have been Lopez’s best friend, but it’s not quite so simple. Lopez has appeared in 14 games this year. In his first two starts on April 7th and April 16th, he was absolutely destroyed. This is Lopez’s first year above Rookie ball, and it’s not really surprising that this would happen, and while I’m loathe to simply discount stats I don’t like understand that:
- Dean and Berberet caught those first 2 starts.
- Lopez has allowed 6 HRs on the season. 4 came in those first two games (3-Dean, 1-Berberet).
- That in his 2nd start against the Cedar Rapids Kernels (52-33), Lopez recorded only 1 out while the Byron Buxton led Kernels batted around. Lopez’s FIP for that game was 223.2. Which is bad.
- Lopez struggled in his first turn with Coulter behind the plate as well, though not to such a disastrous extent. He made it through 5.1, but allowed a HR and walked 2 (and drilled a guy) while only striking out 2.
If we eliminate the month of April, things look better for everyone involved.
Berberet – 3.610
Dean – 2.2
Coulter – 3.138
So again, things look good for Coulter. Dean jumps a ton only because he only caught Lopez twice and this eliminates a game. At this point I’m just including him for the sake of completeness. The funny thing about this is Berberet has caught every recent game – Lopez’s “breakout” – but you can make a decent argument not only that Coulter was better behind the plate, but that Lopez’s breakout happened as early as May 5th.
Now, there are a few other things worth mentioning. In May, Lopez alternated starts and relief appearances. If we remove relief and just look at starts:
Berberet – 3.917
Coulter – 4.819
Coulter looks much better due to two Lopez relief appearances. On May 5th Lopez worked 4 innings of relief, walking 1 and striking out 3 for a FIP of 2.45. On May 17th he worked 3.1 innings of relief walking 2, but striking out 6 for a FIP of 1.265. Coulter caught both games, and while Lopez did throw significant innings, relief is often easier for a number of reasons (working against the bench, able to throw your best stuff more frequently, etc.). With Coulter behind the plate Lopez has K’d 22 batters in 22 innings, but relief appearances contributed greatly to that. With Berberet it was only 20 Ks in 29 and two thirds.
The bottom line is as follows. From April 29th to May 23rd, (early) Coulter caught Lopez. In starts he had FIPs of 6.14, 5.53, and 3.36 (in chronological order). Lopez had his only two instances of 5+ walks in two of those starts but he also had his only 7 K performance.
From May 28th through July 3rd, (recently) Berberet and Dean caught Lopez. In his starts he had FIPs of 4.033, 2.87, 2.2, 3.93, 2.7, and 2.6 (in chronological order).
And at this point I will simply declare that you can’t tell anything about the catcher’s influence on anything. It would make as much sense to say that he was simply bad/adjusting early and got progressively better. Sure he wasn’t as good in 3 starts with Coulter but that hardly seems fair, and he did get progressively better with him over time. The fact that this progress continues as time goes on is merely an indicator of a pitcher continuing to get better. I was looking for a drastic jump and for Lopez to be consistently bad under Coulter but there’s certainly not enough data to say that, and even looking at what we have, Berberet and Coulter are too close to draw any firm conclusions without resorting to statistical gymnastics. Cutting out all relief appearances is hardly fair when they’re 3+ innings, and it involves not only cutting out some of Coulter’s best appearances, but also one of Berberet’s worst, a one batter relief appearance in which Lopez allowed a HR.
Just to cover my bases a bit I took a look at the two pitchers who have thrown more innings for the Rattlers than Lopez**: Tyler Wagner (3.63 ERA, 89.1 IP) and Eric Semmelhack (4.68 ERA, 75 IP).
Tyler Wagner, FIP by catcher:
Berberet – 2.40
Coulter – 4.15
Dean – 6.18
Tyler Roberts – 5.577
Looks good for Berberet, but…
Eric Semmelhack, FIP by catcher,
Berberet – 5.323
Coulter – 5.033
Dean – 4.19
Roberts – 8.1
So in answer to the title, probably not.