Puzzles

Should we expect a dropoff in productive batted ball profiles, from an angles perspective, for minor league hitters when they make the jump to face major league pitching in their first full stint?

I’m assessing a hitter’s ability to create productive angles using metrics like Average Launch Angle, Pull Rate, and Sweet Spot%. Pete Crow-Armstrong is an example of a hitter who produced good batted ball angles during his minor league career, or at least during his time at AAA (the level we have ball flight minor league data). I wondered if we might see a dropoff for him in these metrics, hypothesizing that hitters might tend to do so in the jump from AAA to the major league level, where pitchers have better stuff, command, ability to gameplan for opposing hitters, stronger defenses, etc. To me this was interesting, especially in the evaluation of a guy like PCA, who relies on his batted ball profile for so much of his offensive production. If he were to fall off in this area, he doesn’t have great impact quality to lean back on to maintain solid performance.

Looking at hitters who made their major league debuts between the start of the 2023 season and now, we generally see the opposite of what I had hypothesized. Below are the correlation coefficients of various batted ball metrics between a hitter’s last AAA stint and first MLB stint, limiting the sample to hitters who had at least 80 batted ball events in each and controlling for some other aspects, like length of stint (i.e combining PCA’s 2023 and 2024 minor league metrics into one stint due to how short his 2023 MLB campaign was).

We see some pretty strong relationships in regards to a hitter’s ability to carry their AAA batted ball profile into the big leagues.

And instead of just looking at relationships for individual metrics, I also tried to capture the similarity of a hitter’s batted ball profile as a whole from AAA to MLB. To do so, I calculated the squared difference between normalized values across these metrics and translated it into a similarity score percentage. This essentially combines the differences in each of a hitter’s batted ball metrics between the two levels, and combines these differences as one “score”. If a hitter were to have a 100% similarity score, that would show signal that there were no differences in each metric between AAA and MLB.

Of the 51 hitters in the sample, none fell below an 81% similarity score and the group averaged at 90%. This seems pretty good intuitively, although truthfully I don’t know how to interpret the significance of an 81% similarity score, especially within the context with which we’re using it. But I at least wanted to get a more holistic understanding of batted ball profiles and how they translated between AAA to MLB.

Circling back on PCA - his batted ball profile has looked pretty good so far. Below is a comparison of his percentile ranks (rough) between his last AAA stint and this year’s MLB performance.

PCA contributes in plenty of ways on the field, but despite his ability to create productive angles with the bat, he’s been below average offensively. Time will tell whether he can add some impact quality to the profile in attempts to raise that ceiling, or even just the floor. But that raises another question of whether doing so might come at a tradeoff of sacrificing productive batted ball angles.

*Data is through August 24th, 2024*