Acuña shakes up debate on comps with Soto

Imagine Ronald Acuña Jr. with Juan Soto's plate discipline. Wait … you don't have to imagine.

None of us are surprised by Acuña's red-hot start to the 2021 season -- the .429 batting average, .881 slugging percentage, 1.371 OPS and 18 hits through his first 11 games. He's a superstar. But we're also seeing what happens when a superstar adds a new dimension to his game. Acuña's elite numbers aren't new, but there's something new underlying them.

Check out the hitters who are chasing the fewest pitches outside the strike zone this season.

Lowest chase rate, 2021
Of 243 hitters with 50+ out-of-zone-pitches seen
1) Brandon Nimmo (NYM): 7.7%
2) Myles Straw (HOU): 8.5%
3) Ronald Acuña Jr. (ATL): 9.6%
4) Max Muncy (LAD): 10.9%
5) Robbie Grossman (DET): 12.0%
6) Juan Soto (WSH): 12.5%

Most of that leaderboard is famously patient hitters -- Nimmo, Muncy, Grossman, Soto. But Acuña? We haven't seen this from him before.

Acuña's chase rate by season
2018: 23.6%
2019: 24.0%
2020: 20.0%
2021: 9.6%
MLB average from 2018-21: 28.0%

Acuña is swinging at fewer than one in every 10 balls -- he's only chased eight of the 83 pitches he's seen out of the zone. And he's chasing less than half the pitches he was last season -- last year, he swung at one in every five balls. He's never chased a ton, but this is a huge improvement.

That adds a whole new potential layer to the Acuña vs. Soto debate. Soto's elite plate discipline is his signature. A handful of games doesn't put Acuna on that level. But if he keeps this up? If this is a real change to Acuña's approach? Acuña could somehow reach even newer heights as a hitter.

We can already see the fruits of Acuña's improved discipline. Those fewer bad swings are leading to more contact when he does hack.

Acuña's strikeout rate by season
2018: 25.3% (20th percentile of MLB)
2019: 26.3% (19th percentile of MLB)
2020: 29.7% (14th percentile of MLB)
2021: 14.3% (86th percentile of MLB)

Acuña's swing-and-miss rate by season
2018: 26.6% (33rd percentile of MLB)
2019: 27.7% (26th percentile of MLB)
2020: 29.9% (28th percentile of MLB)
2021: 16.2% (89th percentile of MLB)
MLB average from 2018-21: 25.4%

Acuña has cut his strikeout rate by more than half, and his whiff rate nearly in half. He's gone from striking out and swinging and missing more often than league average to far under it.

And the thing is, he's not being less aggressive in attacking strikes. Acuña's swinging at more pitches in the zone this year than he was last year, and his in-zone swing rate is in line with where it was in 2018 and '19. He's also swung at all but one of the pitches he's seen that are right down the middle in the strike zone, giving him the highest "meatball" swing rate of his career so far.

Acuña's in-zone swing rate by season
2018: 70.2% (85.6% meatball swing rate)
2019: 68.6% (87.3% meatball swing rate)
2020: 63.7% (80.3% meatball swing rate)
2021: 68.0% (92.9% meatball swing rate)

There's one last layer to all this, and it's the type of pitches Acuña is laying off when they're out the zone and attacking when they're in the zone: breaking and offspeed pitches.

Acuna's chase rate against breaking and offspeed stuff -- the sliders, curveballs and changeups that are so hard to hit if you chase them -- has plummeted.

His in-zone swing rate against those same breaking and offspeed pitches has spiked.

When you attack secondary pitches that stay in the strike zone, you can hit them ... and Acuña is. He's whiffing on a lot fewer breaking and offspeed pitches than in previous seasons. (Fastballs, too, for what it's worth.)

All of this has meant fewer strikeouts for Acuña -- without sacrificing his elite level of contact. And that makes him an extremely dangerous hitter right now. Well, an even more extremely dangerous hitter. As if Acuña wasn't great at enough things already, he's added one more in 2021.