Predicting Kwanghyun-Kim’s performance in US

By Byung Joon Yoon

This time, I will write about Kwanghyun-Kim, who was negotiating a contract with San Diego Padres after being posted for 2 million dollars. Now, while his contract negotiation failed, let’s have a brief look at what may have come about if he had played in the MLB.  Taking data from pitchers who moved from Korea to Japan(or vise versa), and Japan to US. We will then compare that to Ryu’s performance to reach a conclusion. Now, let’s examine players who played in both Korea and Japan, pitched over 50 innings each country, and after 1990. Note that this after 1990 constraint was set up to reflect fairer evaluation of KBO, because I believe performance of players who came from Japan to Korea right after KBO started in 1982 will not help us predicting performance of a pitcher who pitched 30 years later. Their respective statistics are as follows:

Screen Shot 2015-01-28 at 9.12.21 PM

As you see, ERA, K/BB, OAVG are all quite closely related. So, building a regression line:

Screen Shot 2015-01-28 at 9.13.47 PM

JPN.era = 1.3148+0.7077*KOR.era

JPN.kbb = -0.4561+1.1543*KOR.kbb

JPN.oavg = 0.11445+0.66285*KOR.oavg

Est. performance of Kwanghyun Kim in JPN: ERA: 3.65 with K/BB: 1.55, Oavg: 0.315

It is to be noted though, there has been some health issues regarding him that affected his performance from 2011-2013, so if we can assume that he is healthy (which it looks like he is, from what we’ve seen in 2014), this statistic may be underestimating his true capability. Also, because his main issue was partial facial paralysis from stroke, it can indicate that he probably won't suffer from overworking his arm and shoulders, as many others does, and he is still 26. Unfortunately, with the contract negotiation deadline passed, it may be another season before we see how accurate my predictions are.  Next time, I will return with estimated changes in performance for players that moved from Japan to US.

0 thoughts on “Predicting Kwanghyun-Kim’s performance in US

  1. I think it's unreasonable to use past Japanese players MLB statistics to predict possible season stats on a different player coming over. It's false cause. The past asian pitchers to come to the MLB have no effect on this pitchers performance in the MLB. Even if you were to make a judgement of his worth on overall trends, style of play and team worth are variables you can't account for.

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