How Well Did Hyun Soo Kim Handle Fastballs In Korea?

The growing concern around the Orioles spring training camp with Hyun Soo Kim was largely about his inability to hit MLB quality fastballs.  When he cheated and quickened his swing to catch up to mid 90s heat, he was particularly susceptible to breaking balls.  However, when he sat back and hit like he did in Korea, fastballs would simply eat him up.  It made me wonder how exactly did he fare in the KBO.  Is there anything that indicates that this is just a rough patch and that the professional hitter is still alive and well? Those 40 spring training at bats simply are not enough to show his soft skills.

Dan, over at MyKBO, pointed me toward this database.  My Korean is poor and my translation software is spirited, but I had to ask a friend what certain categories were.  For instance, what I thought was bottle flesh was actually Grounded into Double Play.  To say the least, it was a learning experience.  Anyway, from this database I was able to see how Kim performed against all of the pitchers he has faced over the past five seasons.  From there I was able to cross reference pitchers that appeared in both my Pitch F/X source and in this spreadsheet.  Of course, the velocities are not from the same time period.  In fact, most of the velocities are taken about one to four years before Kim ever faced them, so we can tentatively assume that the values probably overstate velocity.  Still, I think it gives us some idea.

The second issue was that there is not much crossover between my MLB Pitch F/X values and what one may find on the mound in a KBO game.  In fact, I was only able to come up with 139 plate appearances where Kim faced a pitcher for which I had fastball velocities at some point in his career.  I wound up doing a simple batch approach.  I would compare pitchers at the halfway point for average fastball velocity, which nicely coincided with 90 mph.  Mind you, pitchers in the Majors with a fastball velocity on average of 90 and below constitute about 15% of the pitching population.  In Korea, it appears that it may be closer to 80%.  An overwhelming majority of 90+ mph throwers in Korea are foreign players and many of them do not throw that hard either.

Keep in mind that these values do not establish true talent levels.  You need about 200 PA for that.  However, it is plausible to consider extreme differences as suggesting underlying concerns.

Kim	PA	2B	HR	AVG	OBP	SLG
>90 mph	70	1	0	.245	.400	.264
90 or less	69	3	8	.365	.406	.794

Perhaps, the most interesting thing that stands out is that Kim was teeing off on pitchers throwing less than 90 mph.  Kim averaged a home run in a little less than nine plate appearances against soft tossers.  Add a little heat and the only extra base hit he mustered was a double.  It appears, based on this small sample, that Kim had a different approach when facing harder fastball throwing pitchers, which was to work the count and be more defensive.  It appears to have resulted in more walks and a collapse in power.

Of course, all batters fare worse against higher velocity pitchers and it may be in an environment like Korea that one gets use to the range of velocity there.  In other words, perhaps elite bats are able to adjust and adapt to higher velocity environments when they encounter them.  With this in mind, I did the same thing for Jung Ho Kang.  With Kang, the same size was worse with 84 total plate appearances.

Kang	PA	2B	HR	AVG	OBP	SLG
>90 mph	30	0	2	.154	.233	.385
90 or less	54	3	7	.364	.426	.909

In comparing the two players, they both struggled mightily against higher velocity competition.  In this very small sample size, Kang gives some hope as he did flash the ability to take high velocity pitchers deep.  However, these numbers would have to improve for him to be a viable bat in MLB.  And, he did.  Some of his hitting last year was a tad on the fortunate side, but he did show a MLB quality bat while what we see above would find that to be highly questionable.

So what does it all mean?  If anything, start Hyun Soo Kim against Marco Estrada.  We should feel pretty confident there.  The rest?  The warning signs are there and it still seems possible Baltimore might try to see what Kim can do, begrudgingly.