While it may seem like a wave of Japanese players have come across the Pacific to the U.S., the numbers aren't so large when you start isolating by position. There have been only three pitchers in the last 10 years who, starting from Japan, came to the U.S. to pitch at least 120 innings in a major league season -- Daisuke Matsuzaka, Hiroki Kuroda and Kazuhisa Ishii. Another notable Japanese starter -- Kei Igawa -- came to the U.S. 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 starters -- I came to the conclusion that there is a substantial difference in the performance of relief pitchers who worked in both Japan and the U.S., and the performance of starting pitchers.