clock menu more-arrow no yes

Filed under:

Jung-Ho Kang is a normal baseball player

All eyes have been on the Korean shortstop since the beginning of the season, and he hasn't disappointed. What's notable about the way he's performed is just how 'un-notable' it actually is.

Jesse Johnson-USA TODAY Sports

There's been a lot written about Jung-Ho Kang, both in the past few weeks and since the beginning of the season. Here is FanGraph's Jeff Sullivan's take from earlier this week, and here's my colleague Nick Stellini's from May, and here's my colleague Cody Callahan from April.

Kang has played under increased scrutiny as the first hitter making the jump from the Korean Professional Baseball League to MLB, and thus far he has thrived. His second half has been particularly exceptional, to put so numbers behind it:

BB% K% OBP ISO wRC+
First half 7.1% 20.2% .348 .116 111
Second half 3.4% 19.3% .420 .288 201

To be fair, those stats are a grand total of 21 games, but those are ridiculous numbers, and for any player to put those up over a month or so means that they are probably quite talented. The April article I linked to above contained the following sentence: "The only thing we know with some level of certainty is [Kang] will strike out a great deal." His K% in Korea: 21.2%. His K% in North America: 19.9%.

The main point of that article was completely valid, however: there was a ton of uncertainty around Kang's performance but there is much less now. Kang is good! Maybe that seems like an obvious statement to make about a decent-fielding shortstop and third baseman running a 134 wRC+, but given how uncharted the transition from the KPB to the MLB was it's still a bit of a revelation.

I set out to embrace the Kang-mania, and try to find some explanation for his torrid start to the second half. I didn't expect to explain why he's been better, but hoped to cover some of the how. This first table shows the rates of pitches he's seen in the first and second halves, with all this data coming from Baseball Savant.

Hard Breaking Offspeed Zone%
First half 61.9% 25.5% 11.5% 40.6%
Second half 59.8% 29.9% 10.3% 42.6%

Hrm. Almost literally no change, across any of the categories. Maybe a slight decrease in the rate of hard pitches and a slight increase in the rate of breaking pitches, but probably just noise. League average rates of hard, breaking, and offspeed pitches: 62.1%, 24.7%, and 11.9%. League average rate of pitches in the strike zone, per Baseball Savant: 39.3%.

Pitchers haven't seemed to treat Kang any differently than most batters, nor have they adjusted at all after Kang's first half. Many rookies see all fastballs until they can prove they can hit them: not Kang. Others can hit a fastball, but reveal a major weakness to a major-league changeup or curveball and see increased rates. Not Kang! Pitchers seem to have taken his KBO experience as legitimate even before his breakout second half. Kang has been pitched extremely normally, if that's a thing.

As you can probably tell from the above table, Kang hasn't demonstrated an inability to hit any single major-league pitch. He unsurprisingly has a lower contact rate on breaking and offspeed pitches, both 66 percent versus 81 percent for hard pitches, but he also takes more of them for balls, 39 percent and 46 percent versus 35 percent for hard pitches. By contrast, another heralded rookie, Joc Pederson, has had some trouble with breaking balls, running a 55 percent contact rate (compared to 66 percent for hard pitches and 65 percent for offspeed) but taking only 38 percent of them for balls (compared to 43 percent of hard pitches and 40 percent  of offspeed). I wouldn't be surprised to see Pederson facing more curveballs in the future, but Kang's offensive game seems very well-rounded.

Next, location. Here's where the pitches to Kang have gone, from the first and second halves of the season:

There are more fluctuations in the second half heatmap, as it's built off a fewer number of pitches, but it also seems to show the first real difference between Kang's first and second halves, with pitchers nibbling around the edges of the zone a little more. Of the pitches thrown to Kang, 6.4 percent were in the exact center of the zone in the first half, but that's fallen to 4.2 percent  in the second half. Pitchers probably don't ever try to throw a pitch in the literal center of the strike zone, but it seems like they're a little more worried about grooving a pitch to Kang than they were previously.

This, like the pitch rates, is not shocking when viewed alongside his zone profile (from Brooks Baseball):

The chart shows nothing too surprising. Kang seems to like pitches in the strike zone, and love pitches high and on the outside half. He is less good against pitches on the outside of the zone. Shocking, I know.

The takeaway from all this is that Kang is a good player, and gets to that point in a pretty normal fashion. He's not going to maintain a 200 wRC+, as he has been since the ASG, and looking at his approach on either side of the break, that spike appears to be primarily the result of luck rather than a change in approach. He might maintain a 130 wRC+, though, and that would be pretty amazing.

It's odd: he's a normal player, seemingly without a glaring weakness or massive strength, who is playing well. Most of the time, that wouldn't be fascinating, but Kang isn't most players.

Among fans and analysts preseason, there was a sense that Kang would be different, that the transition from the KBO would change him somehow. Assessing Kang preseason was like trying to tell how nice a car was from 1,000 feet away without glasses (and poor vision like mine). There's a lot of uncertainty, but then you get closer, and realize Kang is, say, a 2012 Volkswagen, a good, reliable car, the last thing you would describe as uncertain. Pitchers, though, didn't seem to have that early uncertainty, as he's been pitched like everyone else all season long. The aggressive normalcy both of him and the league's reaction to him is what's interesting.

Obviously, the big question is what his transition from the KBO says about the players that will inevitably follow him. Kang is only a single data point, or really about two-thirds of a data point and growing as he gets more playing time. That said, major-league teams are undoubtedly going to be a little more involved in the bidding on the next player posted from the KBO, because Jung-Ho Kang is good.

. . .

Henry Druschel is a totally normal Contributor at Beyond the Box Score. You can follow him on Twitter at @henrydruschel.