He leads all rookie pitchers with 1.0 WAR, and is tied with the thus-far sensational position players Evan Gattis and A.J. Pollock. Sunday night, Hyun-Jin Ryu completed six innings against the San Francisco Giants, and though he took a loss, Ryu induced weak contact from a line-drive team. If the national audience was paying attention, they saw perhaps the best rookie in the league.

Ryu allowed four earned runs on the night and only collected a pair of strikeouts, but the lefty had the misfortune of well-aimed weak contact. Said ESPN’s Dan Shulman after an Andres Torres duck-snort single in the fifth inning:

That’s how it’s going: The Giants with broken bats and getting jammed are coming up with hits and the Dodgers have hit two or three on the screws right at people.

Ryu’s 30% strikeout rate shrank to 27% after the outing against the Giants. And though his walk and strikeout totals do not impress, the performance appears more acceptable when we consider the K-resistant Giants lineup:

Despite a somewhat deflating start against the Giants Sunday night, he has already shown the poise we might expect from a seven-year veteran of professional baseball — as he is — and the effective pitches that we might have never expected from the Korea Baseball Organization (KBO).

When we add his impressive demeanor and repertoire to a solid Dodgers defensive and a pitcher’s park, it appears we may have a Rookie of the Year coming to Southern California.

So what does Hyun-Jin Ryu throw, and what does he throw well? According to the default PITCHf/x algorithm, Ryu throws five pitches, but I defy any reader to explain to me the difference between his supposed two-seamer (FT) and four-seamer (FF):



We can also see the PITCHf/x algorithm is confusing at least a few sliders for curves. (Click on the “CU” icon and you will notice a half dozen “curves” clustered with the sliders.) Moreover we can see the two-seam and four-seam fastballs have almost identical horizontal movement and velocity. That suggests to me these are either the same pitch or pitches so similar as to be unworthy of separation.

But what sticks out to me the most, and what should surprise any veteran observer of PITCHf/x data, is that the highest pitch — the pitch with the least “drop,” we could say — is Ryu’s changeup. I have never seen anything like that, especially in a starting pitcher.

Ryu’s changeup registers somewhere around the high 70s to low 80s and has no arm-side tailing action. Instead, it appears to cut away from lefties a little. (Keep in mind, the zero-line on the x-axis above does not indicate zero horizontal movement.) This suggests he throws a straight strange or palmball as opposed to a circle change. I have not been able to see good enough video of his changeup grip to know for certain.

UPDATE: Thanks to commenter bip for pointing out my swapped axes. With x and y in their proper places, we see Ryu’s changeup exhibiting a more normal circle-change tailing action. This makes much more sense — and also nullifies my need to study Ryu’s changeup grip, given its much more normal movement. *Phew!*

Our friend bip also observes — and indeed the correct axes help illustrate this — that Ryu’s change has a lot of variability when it comes to both horizontal and vertical location. This is something worth watching going forward. Perhaps he hones that movement into greater consistency as time goes, or maybe he allows it to flutter like a quasi-knuckleball? It will be interesting to see develop.

Despite the relative lack of arm-side tailing action, The changeup has gone mostly to opposite-handed batters. Take a look at Ryu’s two-strike approach against both righties and lefties:



Almost 50% of his pitches were either sliders or changeups in two-strike situations, but we can see he has used the changeup almost exclusively against righties. I count only three change-pieces versus self-same southpaws.

Which brings us to the slider. Entering Sunday night’s game, Ryu’s slider had accrued the highest linear weights run value of all his pitches. His changeup had a good showing against San Francisco, jumping from 0.00 runs added to its present 0.94 runs saved per 100 pitches. His slider, meanwhile, continues to dominate his repertoire with 3.40 runs per 100 pitches.

Both hands, we can see above, get a hearty spoonful of slider. Click the “(All)” button in the above “Strikes” category. We can quickly see (1) Ryu throws his changeup like mad against righties (one out of every four pitches is a changeup) and (2) he throws his slider down-and-in on righties and down-and-away on lefties — and he does this with almost equal frequency.

I spoke with a variety of KBO fans and observers regarding Ryu and his pitches. The consensus among Korean-based fans was that Ryu’s changeup was his strongest pitch. Jeeho Yoo, sports writer for Yonhap News Agency, and Danny K, founder of MyKBO.net, both felt that Ryu departed the KBO with an MLB-ready changeup.

I discussed Ryu with an MLB scout in Korea and he likewise praised the changeup. He also noted that Ryu’s changeup, which has stayed mostly away from righties, has shown a diversity of location in the MLB that Ryu did not employ in Korea:

His change has always been his best pitch. But something he’s doing more in the US is throwing his change inside on RHB.

Again, with “(All)” selected under both balls and strikes, we can click the blue “CH” icon and notice about 10 changeups coming in on righties (edging over the left side of the zero line). If we filter outcomes (“des2”) to include only hits (“In play, no out” and “In play, run(s)”), we can see see none of these inner changeups have gone for any damage yet.

And while the Korean contingent has good words to share about the changeup, our own Bryan Smith likes the slider most:

Might the Dodgers mammoth payroll have a bargain, after all? Ryu has looked good, commanding his fastball, living on the outside corner, and showing a real good slider.

Smith also thinks — or at least thought a month ago — that Ryu’s curve would not last in the majors. It certainly got the least praise from my variety of sources, and it did not seem to have terribly great effectiveness through his first few starts. Then came the Colorado start:

Why, yes, that is 5 of 12 Ks coming on the curveball. He also had a bat-toss swinging strike (not shown) thrown in for good measure. All this is to echo something Jeeho Yoo said:

Not a lot of lefties can throw four different pitches for a strike, I don’t think, but Ryu has shown he can do just that.

Smith and myself both agree that Ryu’s fastball is not a strength. The pitch has solid, but not blazing speed, and it lacks the movement to be much more than a change-of-pace for his changeup, ironically. His three other pitches, however, have enough movement and life to allow him to use his fastball to setup other pitches or to catch hitters off-guard with a burst of speed.

My Korean contacts also confirmed that Ryu had the mental mettle necessary for sustained success at the MLB level. This is an element we do not stress a lot at FanGraphs because we cannot objectively, or at least partially-objectively, evaluate. But the reports from the peninsula have given every sign that Ryu has the odd and necessary blend between competitiveness, laid-backness and playfulness that composes a player who gets along with teammates and works hard — at least every fifth day.

Said MyKBO’s Danny K:

I like that he’s also relaxed and a joker. When the Dodgers brawled with the Padres earlier this season, I liked how the pictures of Ryu were just him standing there with his hands in his pockets.

Relaxed might not work for some players or some positions, but I prefer stoic, un-rattle-able pitchers than excitable, exploitable pitchers.

I think many rookies struggle with nerves. It is again an issue quite impossible to quantify, but nerves can ruin an inning or likewise an outing. In his major league debut, Yu Darvish admitted to being out sync with his body. Darvish came to the US looking to prove himself as one of the greatest, if not the greatest, pitcher in the world. Ryu seems kind of like the pitcher who crosses the ocean just to see what’s on the other side.

Given his likelihood to improve his ERA as a mere byproduct of playing in the Dodgers’ stadium with the Dodgers’ defense; given his impressive outlay of pitches and early signs of sustainable success; given the prosperity of circumstances that landed him in the starting rotation from Opening Day; and given his mental acuity and pro experience, it seems quite likely the other side of the ocean had a ROTY award waiting for him all along.

NOTE: I want to send along thanks to the many people who helped with this piece. Also, I want to throw a plug out there for the amazing work Clint Husley does at I R Fast (see his KBO WAR piece). Though I did not have an opportunity to use his work, I have found his blog a potent tool in navigating KBO data.

And speaking of things I didn’t have a chance to use, he’s another interactive visualization — a bonus! This one is designed to show the called balls and strikes for Ryu. It looks like, at least anecdotally, that Ryu is not getting the “lefty strike” with any consistency. The lefty strike is the zone between -1.0 and -1.4ish that typically goes for a strike against left-handed batters. The lack of a lefty strike could be, however, a product of bad framing from the catcher or a clustering a umpires who call tighter zones. I’m not sure.

