Ronald Acuña Jr. is Typically Different

One of my favorite ways to find interesting stats about baseball is to use the strangely unheralded Season Stat Grid on FanGraphs. How I use this resource the majority of the time is comparing the most recent season to the only immediately prior, and seeing the biggest year-to-year changes in either direction for some metric. The brevity of the 2020 season has largely robbed me of that pleasure; looking at changes isn’t worthwhile if said changes are simply due to small sample flukes, or to a massive decline in playing time. There is, however, a little bit of enjoyment I can salvage by examining changes in rate stats that stabilize quickly (I’ve discussed those before in my Andrew Knapp article). Even in this pared down version of this exercise I so enjoy there are a plethora of takeaways about which I could write. One in particular was especially notable, though, and it seemed preposterous to me that no one had previously discussed it. So I guess I will. Ronald Acuña Jr. is a much different player than has been in the first two years of his career.

Acuña is clearly doing something different in 2020. He has had the biggest BB% increase from 2019 among all MLB players and is in the top 20 in increased avgEV and Hard Hit% as well. Of course, when a hitter walks more and hits the ball harder in the air, they’re going to perform better. That makes sense and doesn’t need to be scrutinized. Acuña, however, has never walked like this before at any level of professional baseball. What changed?

Unlike in my investigations into Knapp (linked earlier) and Byron Buxton (linked here), Acuña has broken out in a traditional manner. The way he’s achieved this breakout also makes sense. His swing rate has dropped 4.8% and his chase rate has gone down 4%. When someone is more patient and chases fewer pitches they walk more. Thus, Acuña is walking more.

He is aiming up with his swings and hitting the ball harder, partially due to increased patience allowing him to swing more aggressively, but also in a seemingly intentional effort to do exactly those two things. Now, in addition to his very good defense and elite base running, Acuña is among the best hitters in baseball. With this combination he could very well be the successor to Mike Trout‘s crown.

At this point I must confess something. This is my third article in a 6-day span about a player with a drastic offensive improvement in 2020. All three of them did so in a different way. Buxton stopped whiffing and used this new ability to swing at everything he could; Knapp ignored crush-able pitches to work deeper counts knowing he could still serve bloop hits over the infield; Acuña is doing the traditional walks and power upgrade. It’s no accident that these were all clustered so close together. Yes, I wrote these articles to share that these three players were having great seasons. But the true goal was to illustrate the myriad of ways in which improvement could be achieved. The Acuña breakout is the classical idea of how an offensive breakout should look. Clearly this idea is still effective, as Acuña is showing. Yet Buxton and Knapp are showing other effective ideas, ones no one, myself included, would have envisioned working as they are. There’s an oft-used cliché that baseball is a humbling game. The improvement methods no one ever could have expected shows that this adage holds true for those analysts like myself who think they’ve thought of everything about baseball. Baseball will always produce something totally new to strike us all down.