The Cardinals have agreed to a two-year deal with Korean pitcher Kwang-hyun Kim. My fellow authors here have done a nice job covering the deal from a variety of angles, but I’m going to add my own perspective, strictly from watching video of Kim. I knew the name coming into the offseason, but honestly hadn’t paid that much attention to where posted players might be ending up. Well, until now, of course.
So what I’ve done since Kim to the Cardinals became a possibility, then a reality, is watch as much tape on the guy as I have been able to. As is the case with most star Asian pitchers, you can actually find quite a lot of video on them if you search, although admittedly very, very little of it will feature any English. However, the language of baseball cuts right through differences in tongues, and so, as long as you have a km/h to mph conversion ratio handy, watching a Korean or Japanese pitcher is really not that much different from watching a guy born in Tallahassee.
There’s an interesting point I have to make about Kim right off the bat, which is that watching video of him from the early part of this decade is a very different experience than watching more recent tape. When he was a younger pitcher, his arm slot was significantly higher, almost Kershawesque, and he approached the game very much like a power pitcher. Problem was, he really didn’t have overwhelming stuff, just good stuff, and his lack of command hurt him.
In 2017, however, Kim had Tommy John surgery, or rather missed the 2017 season after having TJ (I couldn’t find an exact date on the surgery itself), and since coming back his arm slot is lower, closer to 3/4, and his stuff has actually improved. Even better, he now pitches more like a finesse pitcher, but with power stuff, and looks like a much, much more dynamic talent now than he was earlier in his career. We’re used to the aging curve dictating players, particularly pitchers, peak at a certain age (and earlier than we usually think), and they begin to fall off quickly as they move into their 30s. Kim, on the other hand, is one of those odd hurlers who actually seems to be hitting his stride at 30/31, sort of like Cliff Lee. Of course, Lee was also done by the time he turned 36, so it’s still less than ideal for a pitcher to wait until he hits 30 to really turn on the jets.
I’ve watched a bunch of video, as I said, but for reference, this is the best overall representation of Kim I found. It’s a full game’s worth of pitching from late in the 2018 season, and I would love to credit the poster of the footage if I could read Korean. Sadly, I cannot, and so I will have to simply thank whoever put this up, because it made my job here much easier.
So there’s a lot to unpack here, but to start off we’ll simply deal with the velocity. Throughout this game, and most other games I’ve seen, Kim’s standard fastball ranges from about 90-93, with a tick or two more available here and there. I think those who say he ‘sits’ in the mid-90s are being a bit too generous; he’ll touch 95 here and there, but is solidly about 91-92 for the majority of his work. And that’s fine. Velocity has become an overriding narrative in the game these days, but location and movement are still just as important in defining the quality of a fastball as the pure radar gun reading.
Complementing the heater, Kim leans heavily on a slider that he’ll add and subtract with, ranging from about 82 all the way up to 88. That ability to push a little, or back off a bit, on the slider without losing the break on the pitch, is a little reminiscent of Patrick Corbin, who has pushed himself into elite territory by leaning on his best pitch and varying it up. I don’t have pitch usage data on Kim, but if anything I would say he could probably go to the slider even a little more often than he does here, simply because the pitch is so good.
In addition to the slider, Kim features a softer, loopier curveball mostly in the mid-70s, and a roughly average-looking forkball in the ~83 mph range. I hate to make a comp that seems too easy, but I promise I’m not just making it because they’re both Korean: Kim’s approach and repertoire are somewhat similar to that of Hyun-jin Ryu. Now, Ryu’s changeup is a differentiator here, being much better than Kim’s splitter, but I would argue Kim’s slider is stronger than Ryu’s breaking ball, so you’re trading usage between two offspeed pitches a little bit.
Let’s talk about how the pitches work now. Kim’s fastball is firm, and it seems like it has solid movement. He’s got a bit of natural cut on the ball, and to my eye he looks stronger working to the glove side (third base), than to the arm side of the plate. That slight cut actually helps his slider play up, I think, because the fastball and slider tunnel a little bit better than some other pitchers. If forced into bullpen duty, I would think Kim could lean on the fastball/slider combo and put up some tremendous strikeout totals, but his arsenal is wide enough, and strong enough, that I see no reason to push him toward relief work anytime soon.
The curveball is interesting, and again, similar to that of Ryu. Ryu mostly works fastball/changeup/slider, but he’ll toss a bigger, softer breaking ball up there occasionally, oftentimes early in the count, trying to get a hitter to take a strike. Kim’s curve is similar, in that it’s big and slow and loopy, and not really tight enough to get many swings and misses, but it can be enough of a gear change that a hitter will take it rather than swing. Early in his career, Kim always attacked early with the fastball and then tried to get a swing and miss with a slider in the dirt; watching him more recently, he’s much more inclined to steal that first strike with a curveball or slider, then force the hitter to expand upward on the fastball. Some pitching coaches love pitchers who are willing to work backward, while others subscribe to the dogma that everything has to play off the fastball. I fall more into the former camp, and Kim’s willingness to vary his approach from hitter to hitter is very encouraging to me.
I would like to point out the curveball at 7:53 in the above video, which really goes against what I’ve said about Kim’s curve in general so far. The pitch comes in at just about 71 mph, which is decidedly slow, but he buries it for a swinging third strike. That’s really interesting to me, in that it suggests he might be capable of spinning the ball more aggressively than he usually does on the curveball, and chooses to use the pitch in a certain way most of the time, rather than not being able to break off a hard curve at any point.
As for the splitter, I’d put about an average grade on it, and point out that Kim tends to get a little more of the plate with the pitch than I would prefer to see. When he works down and away out of the zone to righties with the split, it can be effective. But the pitch doesn’t have quite the deception or movement to work inside the zone, I don’t think. That being said, he does have four usable weapons on the mound, and that helps each of them play up.
The real question, of course, is how well the stuff will play in the majors, and a big part of that is the issue of Kim’s strikeout rate. He strikes out a very good percentage of hitters in the KBO, but it’s not the sort of K rate that sees so dominant as to demand an MLB club pick him up. Personally, I’m not overly concerned about the stuff or the strikeouts, largely because in Korea the strikeout rate in general is significantly lower than in MLB. Now, some would argue that is due to the quality of the pitching, and for the most part I have subscribed to that theory up to this point. However, having watched Juan Soto play, I have starter to wonder. Yes, he is obviously a remarkable talent, but I admit I’m beginning to wonder how much of that hitting excellence really does come down to just simply having a two-strike approach at the plate, at all. Soto is one of the only players in the game right now who actually alters his overall approach based on the count, and I do wonder how much of his ability to avoid huge strikeout numbers while working an incredibly patient approach which often leads to deep counts comes down to willingness to commit to an approach, rather than some utterly miraculous physical skill. (I’ve wondered the same thing watching Joey Votto, too.)
In Korea, there is much more of a focus on contact hitting than here in the US, and I have a feeling Kim’s strikeout rate will not drop much, or perhaps any at all, coming here from Korea. The competition may be stronger overall, but I do think American hitters are much more comfortable taking their hacks and heading back to the dugout.
So what do I think of this signing? Well, not to sound hyperbolic, but I’m frankly thrilled. It’s not the Gerrit Cole signing I was stumping for early in the offseason, but this is a move with serious upside, I think. Kim’s age is a concern for me, because even with what I said earlier about him reaching a new level at a relatively advanced age, that doesn’t mean that his arm doesn’t already have the mileage of a player about, oh, his age. Pitchers who peak late don’t just get good late and then pitcher longer; they get good late and tend to just have shorter peaks. (See also Lee, Cliff.) However, the fact is Kwang-hyun Kim has actually seen his stuff tick up slightly since Tommy John surgery, and he has become much more of a control pitcher than he ever was in his younger days, walking below two hitters per nine innings each of the last two seasons. I’m not sure he will be able to develop the kind of precision command Hyun-jin Ryu has come into, but a sub-7% walk rate certainly seems achievable for Kim, and his stuff should play in the majors, I think. I don’t see a serious platoon issue, and he’s got at least one pitch in the slider that he should be able to lean on consistently to get swings and misses against any level of competition.
I doubt this is in any way a possibility, but my hope for Kim would be to push his way into the rotation, and for the Cardinals to actually employ Adam Wainwright in swingman sort of role. I worry about Waino shouldering a full starter’s load again this season, while I’m hoping to see Carlos Martinez transition back into the rotation. Wainwright was good in 2019, but I have serious doubts he can carry another 170+ inning season to completion. Something more like 90-110 innings, with him leaning on his best stuff in more concentrated bursts, would seem an optimal solution to me. Kwang-hyun Kim, on the other hand, I see no reason not to believe he can transition, quite successfully, into a major league rotation.