While it may seem like a wave of Japanese players have come across the Pacific to the US, the numbers aren’t so large when you start isolating them by position. There have only been three pitchers in the last 10 years who came from Japan to the US to pitch at least 120 innings in a major league season. Those three: Daisuke Matsuzaka, Hiroki Kuroda, and Kazuhisa Ishii. Another notable Japanese starter-Kei Igawa-came to the US with the intention of starting, but he failed to make the grade. This year, though, we have two more Japanese starters here to try their luck: Kenshin Kawakami with the Braves, and Koji Uehara with the Orioles.

Translating statistics between different leagues is a difficult enough task under the best of circumstances; translating across different cultures is even harder. A funny thing happened as I was researching this piece and zeroed in on Japanese starting pitchers-I came to the conclusion that there is a substantial difference in the performance of relief pitchers who worked in both Japan and the US, and the performance of starting pitchers.

In a typical year, once you correct for the differences in league averages, there is about a 10 percent drop-off in performance for the same pitcher in the US; if an average pitcher in Japan had a 4.50 ERA, you’d expect him to be about 4.95 stateside (i.e., he’s allowing 10 percent more runs). When I re-ran the numbers, though, restricting it to starting pitchers only, I came up with a penalty of about 20 percent. Keep in mind that there aren’t enough Japanese pitchers to analyze; you have to consider all of the American pitchers who go to Japan before you have enough of a sample to start realizing the extent of the problem. It isn’t entirely clear why there should be a difference between starters and relievers; most of the changes should affect starters and relievers equally. It could be that there are more starter-to-reliever conversions going in the Japan-to-US direction; most pitchers benefit from being in relief. Another, more speculative possibility, is that all the starters in Japan benefit from a somewhat more spread-out schedule than in the US. In the NPB, most pitchers go on five, or even six days’ rest between starts; our current standard of four days between starts is short by Japanese standards.

Taking that into account, of the four recent would-be starters, all have nearly matched these revised expectations. Consider the following tables; the pitchers’ stats are averaged and translated to a common standard (where 4.50 ERA equals a perfectly average major league pitcher):

Kazuhisa Ishii     IP    ERA   H/9   HR/9   BB/9   SO/9
Japan 1999-2001   157   5.07   9.0    1.2    4.6    7.5
US, 2002-2005     137   5.13   8.7    1.1    5.1    6.4

Hiroki Kuroda      IP    ERA   H/9   HR/9   BB/9   SO/9
Japan 2005-2007   176   4.13   9.3    1.0    2.2    4.4
US, 2008          187   4.19   8.4    0.6    1.7    5.0

Daisuke Matsuzaka  IP    ERA   H/9   HR/9   BB/9   SO/9
Japan 2004-2006   167   4.15   8.7    0.9    2.8    6.4
US 2007-2008      182   3.94   8.0    0.9    3.8    7.9

All three performed very close to their established, translated Japanese levels. Translating Igawa’s performance by this new method, it’s little or no surprise that he failed for the Yankees:

Kei Igawa          IP    ERA   H/9   HR/9   BB/9   SO/9
Japan 2004-2006   177   5.55  10.1    1.3    3.4    5.8
US 2007-2008       36   5.27  10.8    1.9    4.1    6.0

That’s only looking at the majors; Igawa’s minor league translations lead to a perfectly consistent 5.42 ERA over the past two years, or someone who you probably don’t want in your regular rotation, especially if you hope to contend.

What does this mean for Uehara and Kawakami? Let’s start by pointing out that both of them have had excellent Japanese careers. Kawakami has a Sawamura Award (essentially, the Japanese leagues’ equivalent to our Cy Young Award), an MVP award, and a Rookie of the Year award. Uehara picked up two Sawamura awards. Both are right-handed, they’ll both turn 34 this year, they each rely on a somewhat exotic main pitch-Uehara throws a splitter/forkball, Kawakami a cutter-both have excellent control, and both have relatively average fastballs that can be readily hit.

But there are differences. Let’s start with Uehara, whose last three years translates like this:

Uehara    IP    ERA    H/9   HR/9   BB/9  SO/9
2006     157   5.39    9.8    1.8    1.7   5.4
2007      59   3.05    8.1    0.9    0.9   6.6
2008      84   6.67   10.4    1.7    2.4   4.9

He had leg injuries in 2007, and he was forced to start the year in the bullpen; he performed so well there that the Giants never moved him back to the rotation that season, and he wound up setting a team saves record. In 2008 he started off so badly that he was sent to the minors. He eventually got straightened out right around the time that the Olympics started, and he then starred in Beijing, following that up by pitching well in the second half. Maybe you could say he had more injuries in the first half, though no one has made an official claim that was the case. This certainly looks like a pitcher who is spiraling toward the end of his career; the stats say he still has skills, but limited stamina. The Orioles want him to start, however, and indeed, they need him to start, because their bullpen is full, while their rotation is a set of question marks. Unfortunately for them, as a starter he’s just another one.

On the other hand, Kawakami gives the Braves a more hopeful case, though still not without cause for some doubt:

Kawakami   IP    ERA   H/9   HR/9   BB/9  SO/9
2006      198   4.90   8.5    1.4    2.4   5.5
2007      162   5.68   9.8    1.3    1.7   5.1
2008      110   4.01   8.7    1.3    2.7   6.1

For two of the last three years, Kawakami has not pitched at the level of an above-average major league pitcher, though he did turn it around last year. If he struggles in the US, it will probably be because of his home-run tendencies (considering that the HR/9 column is set so that 1.0 is average). That’s a product of trying to get ahead in the count with an unimpressive fastball-hitters will have their chances to tee off on it. He’s been healthier than Uehara, but he did miss time with a back injury last season, as well as winding up spending some time with the Olympic team last summer.

A third Japanese pitcher with some notoriety this offseason is Junichi Tazawa, an amateur who signed with the Boston Red Sox after a noisy bidding war. He’s more or less the same as a draft pick; the corporate leagues he was playing in there don’t exist here, but are more comparable to Division I college baseball than anything else. Like most American draft picks, he isn’t considered to be anywhere near ready for the majors, so the money invested in him needs to be treated as such, where there are no guarantees.

Thank you for reading

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You think the Yanks talked themselves into it because Iggy throws with his left hand? Or because the Sox had just gotten DiceK? Or a both?
Why do you narrow your criteria like that? It seems you set up your criteria (last 10 years, 120 IP) to ignore Hideo Nomo and a number of Japanese relievers (Sazaki, Saito, etc.) who have come to the US?
For Nomo, I don\'t have his Japanese stats...too far back.

Second, I wasn\'t interested in the relievers, since there aren\'t any new ones coming over. I was trying to work specifically on starters, and was surprised to find that there was a difference in the derived rating, and that became the basis for most of the article.
I think part of Uehara\'s early problems last year were related to his pre-season press conference at which he announced he would declare free agency and move to MLB in 2009. He wasn\'t treated with the same respect by his employers as he would have been had he kept his own counsel. In short, they jerked him around for a while. Based on his stuff, there\'s no reason why he shouldn\'t be a solid number 4-5 guy for at least a year or two.
Are these translations league-specific or just to US ML baseball generically? Perhaps more clearly stated, are those Uehara\'s stats in the AL and Kawakami\'s stats in the NL? Or is it just a generic Japanese starter to US starter translation, with other stuff (like league and division) to be worried about later?
Thanks for the ever-improving translations on Japanese pitchers. One question: since Tazawa is coming from the Industrial League, how important is his single datapoint in giving you insight on that league if he continues on into the majors? Have there been others with an IL background that you can incorporate into your work?
what about Masato Yoshii? 11 years ago, and he pitched 170 innings his first year and 750 over his five
\"Failed to make the grade?\" I wouldn\'t rush to judgment on Igawa. It\'s only been two years and $30 million and the jury is still out on Steel Nerves. He was lights out in Scranton last year and another spring with Organizational Pitching Guru Nardi Contreras will straighten him out.

Oh, wait, I\'m delusional and Cashman was taking my crazy pills when he made that move.
Why exactly are you averaging their statistics with an assumed league average of 4.50 again?