Ah-Seop Son Sure Does Walk a Lot

After the initial sugar rush of watching live KBO baseball faded, I’ve settled into a comfortable routine. While I work and relax throughout the day, I’ll watch some KBO action from the night before, either the English language feature game or a Twitch rebroadcast in Korean. In that way, I soak in the atmosphere of baseball almost by osmosis, sometimes focusing closely on a play but sometimes just listening to the sound of it.

At some point, however, I started to get a sense of déjà vu. Hey, that Ah-Seop Son guy is on base again. Hey, did he walk? That was a nice at-bat there, but haven’t I seen this before? It turns out that yeah, that was the case. Through 61 plate appearances in 2020, Son has drawn 14 walks. That’s a cool 23% walk rate. I wasn’t just imagining things — 14 games, 14 walks. He truly is just walking all the time.

Some quick backup before we cover what’s going on this season: Son has been a mainstay in the Giants lineup for the last decade. Since 2010, his worst wRC+ was a 112 showing in 2019, with a 151 wRC+ effort in 2014 his best overall year. For the most part, he’s been a metronomic presence at the top of the lineup, as his career stats attest — he’s a career .323/.395/.471 hitter, which works out to a 134 wRC+. That’s something like career Will Clark — relative to a weaker competition level, of course.

That career .401 OBP says a lot about his on-base prowess, and indeed, Son’s career walk rate is a robust 11.3%. He’s never been much of a slugger, but the combination of gap power, 20-homer pop at his (and the league offensive environment’s) peak, and an all-fields, line-drive approach have made opposing pitchers careful around the plate, and he’s been willing to take his walks.

But “taking his walks” isn’t what Son has been doing this year. He’s been greedily grabbing them, handfuls at a time. On May 13, he went 2-2 with three walks in a 10-9 triumph over the Doosan Bears. On May 20, he went true-outcome wild; 0-1 with three walks, the one out on a strikeout. Walking 23% of the time and striking out a mere 8.2% seems like a video game, like peak Barry Bonds but without the power that led to all those walks.

What’s a writer to do? Go to the video, of course. I watched all the games I could get my hands on, seeing whether Son had transcended mere mortal status at the plate or was just on a hot streak. The first thing you notice about Son is his stance at the plate. It’s Anthony Rizzo in reverse, a lefty stance seemingly designed to inside-out pitches away while turning on inside pitches:

As you can see, Son isn’t afraid of swinging on the first pitch. That double was one of two first-pitch swings in the game, both lined into left field. He chokes up a little — but that doesn’t mean he’s not taking full hacks out there:

In any case, I went through every plate appearance pitch-by-pitch to see what Son’s line was about. Take all of this with a grain of salt, because I’m approximating the strike zone from an offset angle in broadcasts that don’t have a strike zone graphic and the KBO strike zone differs from MLB’s, particularly in the lower part of the zone. But my friends, here’s what he’s about: rarely swinging at a ball and pretty much never missing anything in the zone he swings at.

An at-bat against Doosan Bears righty Chris Flexen illustrates the difficulty of facing Son. On 0-0, Flexen threw a fastball in the strike zone — Son swung but fouled it back. Flexen came back for more on 0-1, and Son again made contact, fouling another off. Down 0-2, Flexen then went outside the zone. After Son watched the pitch fly by for a ball, Flexen went back to it again. And again. And again. And after four straight pitches that missed the zone, two by not so much, Son stood on first with a walk. Two pitches in the zone; two swings that made contact. Four pitches outside of the zone — one walk.

I must, once more, caution you that these statistics aren’t perfect. They’re my best guesses, and they actually leave out three games due to archive availability on Twitch. But they don’t have to be perfect, because even the approximation says a lot about his approach and unique talents.

First of all, Son isn’t going to swing unless you make him. So far this year, he’s swung at 38% of the pitches he’s seen, a rate that’s comparable to Mike Trout or Mookie Betts (roughly in the third percentile of swing rate) in the major leagues. His 80% contact rate doesn’t stand out — it’s slightly above MLB average, and likely in line with KBO average. But from there, things get a little bit weird.

On the first pitch of an at-bat, Son comes out swinging. In the 47 plate appearances I charted, he swung at the first pitch 44.7% of the time. How rare is that? It would put him in the 97th percentile in the majors — in other words, in the top three percent of the league. He’s incredibly aggressive on the first pitch, then reins in his aggression noticeably from then on out.

Okay, so don’t throw him a cookie to start off the at-bat — easy enough. The only problem is, he’s not indiscriminately hacking on the first pitch. On pitches in the strike zone, he’s swung 68% of the time. That’s literally Willians Astudillo level. On pitches out of the zone, that rate plummets to 18%, middle-of-the-road. And he’s not just trying to punch the ball to left, though he can do that too — he often gears up for power on 0-0. Engaging him in the zone in an attempt to get ahead in the count is a risky proposition.

Why? Because you’re going to have a tough time striking him out even if you do get ahead. In two-strike counts this year, pitchers have challenged Son in the zone 13 times. He’s swung — 13 times. And per my again sketchy data, he hasn’t missed once, though he did whiff on a pitch that looked like a ball but was near the zone. So you’re probably not going to strike him out by blowing something past him.

In that case, you’ll have to get him to chase. It’s definitely possible — he’s seen 36 pitches outside the zone with two strikes and swung at 25% of them. He does miss here — he’s whiffed on four of the nine swings. But most likely, he’ll just watch the pitch go by — that 25% two-strike chase rate would place him, you guessed it, in the third percentile among major league batters in 2019.

In fact, it’s almost never an easy time to go into the strike zone to face Son — he’s swung at 70.1% of pitches in the zone this year, a thoroughly unremarkable rate. You can’t steal a strike like you might off of Trout or Votto by whipping one in there when they’re unlikely to swing. He generates some power there, too — he’ll take that full-windmill swing in advantageous spots, and can absolutely turn on anything on the inside of the plate.

Of course, what are you going to do, throw him a pitch outside the strike zone? He’s swung at just 15% of those so far this year, an impossibly low number. No one has done that in the last 10 years in the majors. So for the most part, if you pitch outside of the strike zone, Son is going to spit on the pitch and take a walk.

Add it all up, and it’s a tremendous bind for pitchers. It’s not even like you can just flood the zone and live with his slap hitting — he has a roughly league-average ISO, and does most of that damage when he gears up for a pitch in an early count. And even if you can get it in the strike zone with two strikes, when his swing is more defensive, that’s not really to your benefit — you’re just allowing a ball in play, and that’s a victory for Son when the count hits two strikes.

Ah-Seop Son will almost certainly never come over to play in the United States. He’s 32, headed into the back half of his career. He’s a part-time DH now, not exactly a defensive liability in right field but certainly not a wizard with the glove. And his stats, while consistently well above average, don’t explode off the page in the same way as, say, Eric Thames 테임즈’ .349/.451/.721 stint in the KBO did.

But with the KBO currently the only show in town, we’re getting a rare chance to see fascinating players like Son who we might otherwise never have heard of. He seems almost like a caricature — the man with Barry Bonds’ batting eye but the power of a mere mortal. It’s delightful to watch him at work, to watch his Votto-esque grimaces after a generous call for the pitcher or his frustration with himself on the rare occasion where he chases a breaking ball. I’m not grateful for many things that COVID-19 has brought into the world, but seeing Son work is certainly a silver lining.

One more thing, by the way: all the statistics in this article are current as of Thursday, May 21. On Friday, Son put up another classic line: 3-3 with two walks, with all three hits singles. He’s terrorizing the pitchers of the KBO, one take at a time.

We hoped you liked reading Ah-Seop Son Sure Does Walk a Lot by Ben Clemens!

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Ben is a contributor to FanGraphs. A lifelong Cardinals fan, he got his start writing for Viva El Birdos. He can be found on Twitter @_Ben_Clemens.

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