Why hasn't Ronald Acuña Jr. played at his MVP level yet?

An analytical dive into what’s wrong with last year’s NL MVP at the plate
San Diego Padres v Atlanta Braves
San Diego Padres v Atlanta Braves / Alex Slitz/GettyImages

Last year was a historic year for Ronald Acuna Jr. He hit .337 (2nd in MLB) with 41 HR (5th in MLB), stole 73 bases (1st in MLB), and posted an OBP of .416 (1st in MLB). He was a no-doubter to win the NL MVP award. This year has been drastically different. So far, he has posted a .247 AVG with 3 HR, 15 SB, and a .355 OBP. The stolen base total is still great and the on-base percentage isn’t terrible, but the Acuna we saw last year seems like a distant memory. What is wrong with Acuna? Let’s go over the data.

Disclaimer: All statistics reflect totals at the time of writing on 5/22

Hard-hit rate

Acuna’s bat speed is among the elite. His average exit velocity this year is 92.6 mph compared to last year’s 94.7. As a result, his hard-hit percentage is 50.4%. This is similar to last year’s 55.2%. So, the problem definitely isn’t bat speed or hitting the ball hard.

Launch angle

A brief look at launch angle doesn’t offer much of a clue either. This year, Acuna’s launch angle sweet spot percentage (LA Sweet Spot%, means the percentage of balls hit that makes contact with the bat at the right spot to produce the most effective launch angle) is 31.2%, not much lower than last year’s 33.6%. So far, his swing is still looking good according to the metrics.

K’s and barrels

When we look at his strike out rate, we see a jump from last year. In 2023, Acuna’s K% was 11.4%. This year, it is 24.1%. This factoid is alarming. But what is behind this? An in-depth look at his Barrels% (the perfect combination of launch angle and an exit velocity of at least 99 mph) reveals a potential culprit. When we look at his Barrels %, we can see that it currently stands at 8%. Last year, Acuna finished the season at 15.3%.  What might this suggest? Before we draw any premature conclusions, we should take a look at Acuna’s numbers against pitch-types first.

Pitch-type results

Last year, Acuna hit .340 against fastballs, .350 against breaking balls, and .288 against off-speed pitches. This year, he is hitting .214 against fastballs, .255 against breaking balls, and .375 against off-speed pitches. Against 4-seamers, he is hitting only .140. The higher strikeout rate and Acuna’s tendency to hit off-speed pitches better than before while failing to hammer fastballs like he used to seem to indicate a timing problem.

Timing issues, while simple as they may be, can be difficult to overcome. While there might not be an instant cure, things like this tend to work themselves out over time. As the ebbs and flows of the game continue, it is very likely Acuna will re-discover the rhythm that made him a super-star last year. Whatever the cause, we hope to see him return to his 2023 MVP form sometime soon.

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