I will admit up front that I have a bias in favor of Erasmo Ramírez. I want to see the kid succeed, and I think he is capable of succeeding. He certainly has had his trials and tribulations, but he also has a good arm and decent stuff. Giving a young pitcher like Erasmo every chance to succeed in light of the challenges of other young pitchers (read: Maurer) is something that I think is in the Mariners best interest as they play the waiting game with the devastated body parts of Cerberus.
To that end, if the Mariners want their hard throwing Nicaraguan to succeed, they may want to consider their use of backstop in his outings. I got into a short Twitter exchange with Shannon Drayer today regarding my interest in why the Mariners keep running out Erasmo with everyone's favorite hunter / outdoorsman / RV aficionado. She ultimately replied that she felt that the difference between Buck and Zunino as catchers for Ramírez would be moot largely due to the fact that Erasmo has hardly been living on the edge. A point that makes sense when you think about how wild Erasmo has been this season, but it got me thinking, just how much of this is because he is actually wild, and how much is because he hasn't been getting the pitches he deserves. I decided to do a rough comparison. I will admit that there are a few imperfections to it, but I wanted to get this written before the game tonight and just get a real rough look at if there appears to be any major backstop difference for Erasmo.
Getting the right comparisons was difficult. Ideally I would have been able to get Pitch FX data broken down by catcher, but I was not able to find this quickly so I decided to do a mockup compared to other pitchers on the staff. Rameríz has pitched 6 games this season (not counting today), 4 with John Buck behind the dish and 2 with Zunino. I didn't feel like Paxton, Maurer, Iwakuma, Beavan, or Young were appropriate comparisons (too few games, two many games with Buck, two few games, two few games, and absurdly tall / not like any other pitcher in the league, respectively).
This left King Félix and Roenis Elías, giving me a righty and a lefty to compare against Erasmo, both of whom had Zunino for their initial 6 games (I cut their samples to May 1st to give a roughly comparable number of starts and pitches.) I then pulled their Pitch FX maps up from TexasLeaguers.com to get a rough idea of what their called strike zones looked like for their respective catchers (keeping in mind that Erasmo has 2 Zunino starts that I was not able to isolate out).
First, the King
You can see that Félix enjoys a pretty expansive zone. Very few pitches have been called balls within the traditional strike zone, and Zunino's framing has saved him a number of low strikes that could have easily been called balls.
Elías' zone is likewise pretty well called:
Keeping in mind that Elías is a lefty and therefore has a bit different look to umpires, he has still managed a pretty favorable strike zone, missing a few on the inner corner, but that is about it. He has also earned a number of strikes well above and below the zone, possibly a product of having everyone's favorite Gator chomping up the pitches behind the plate.
Erasmo's zone, however, paints a different picture.
I count around 17-20 times (across 6 games) that Erasmo succeeded in painting the outside corner for a right handed hitter but was rewarded with dead silence from the umpire rather than the animated called strike he deserved. Furthermore, it appears that Ramírez has received less help outside the zone than his two comparisons here. Based on this quick analysis it appears that Ramírez has seemed more wild than he actually has been because he has received far fewer strikes than he has earned. Namely, Ramírez has not been awarded the outside part of the plate when facing a right-handed hitter. When half the plate is effectively off limits, it really limits a pitchers ability to work around the hitter.
Anecdotally, Buck's stabbing motion when reaching across the plate to grab these outside corner pitches might provide a causal link for the reasoning that Erasmo has received so few outside strikes relative to his contemporaries. While this analysis is not quite precise enough to warrant an immediate switch, it might be worth giving Erasmo an easier time with the pitch framing of Zunino behind the plate and see if it makes an appreciable impact while we wait on the wasteland of pitching prospects to climb out of their injury abyss.
Edit: But none of this really matters if he leaves half his pitches in the middle of the plate.