Lately I’ve been thinking about hitters with platoon splits, and what factors are proving most influential in causing a hitter to struggle versus same-side pitching. Specifically, I wondered whether there were certain pitch shapes that platoon hitters struggled against more than others.

For example, my hypothesis was that we might see platoon hitters have more difficulty when facing pitches with more drastic (above or below average) horizontal approach angles than pitches with average horizontal approach angles, from same-side pitching. These struggles, in my mind, could be causing us to view these hitters as having a general tendency to struggle versus same-side pitching, when in reality, those hitters are actually playable against some same-side pitchers with arsenals made up of pitches with average horizontal approach angles. My thought process here is that I would think platoon splits are due in part to characteristics of a hitter’s swing plane, and the inability of the hitter to match his swing to pitch types from same-side pitching, or at least as well as they are able to when facing opposite-handed pitching. Therefore, the more distinct an angle from a same-side pitcher, the more a platoon hitter would struggle against it.

I analyzed two groups of hitters, those with platoon splits, and those without, from 2021-2023, bucketing performance results for each group using Alex Chamberlain’s Horizontal Approach Angle Above Average (HAAAA) methodology, and compared results between each group by pitch type. Below are results for sliders (regular sliders and sweepers), which is a pretty good representation of what I found for each pitch type.

Splits Hitters (OPS differential >= 0.225):

Non-splits Hitters (OPS differential < 0.225):

Looking at results, there does NOT appear to be the trend I had initially hypothesized. Instead, it appears that the two groups of hitters face similar trends when analyzing performance changes across buckets of HAAAA, but platoon hitters have worse performance across the board, without any trends that would signal specific combinations of angle and pitch type that would give them more or less trouble than others.

 I think this is just too much of a broad scope to derive any meaningful insights. I am inclined to believe that there ARE hitters who fit the description I outlined at the beginning of this post, but they, along with others, were engulfed by the population in which they were grouped. When looking at “platoon” hitters as a whole, I found myself seeing poor performance across all groupings I analyzed. However in a follow-up on this topic, I might be better suited to look at specific instances of hitters who have combinations of pitch type and angle they perform well against.

Doing so would allow me to answer these questions better, along with some others that came with this idea. However, it makes it difficult to analyze platoon hitter performance versus same-side pitching given that a lot of my interest in this topic involves the hitters that currently do not get many opportunities to face same-side pitching, therefore smaller samples. And without access to swing data on the public side, aside from the recently available bat speed and swing length metrics, it becomes difficult to really dive into the interaction of matching a swing to the angle of the incoming pitch.