In case you haven't noticed, the track record of Japanese stars heading to the cauldron of Northeast baseball is not real good. Sure, the Pacific time zone teams have done well with Asian players: Ichiro Suzuki, Hideo Nomo, Kenji Johjima, Shigetoshi Hasegawa, Akinori Otsuka ... all these players have been as good as their first U.S. teams could possibly have hoped. The East Coasters, though? Not so much.
Granted, only five Japanese players have gone straight from the Japanese Central or Pacific League to a team east of the Appalachians. I would argue that Tsuyoshi Shinjo, who joined the Mets in 2001, shouldn't be considered a potential impact player because he really wasn't a star in Japan. That leaves four: pitchers Hideki Irabu (Yankees) and Masato Yoshii (Mets), outfielder Hideki Matsui (Yankees) and second baseman Kazuo Matsui (Mets).
Two of those players were unmitigated disasters. Irabu was jeered by Yankees owner George Steinbrenner and picked up a decidedly unflattering nickname: Head-achy I-rob-you. He was never particularly healthy, and he never pitched particularly well. Kaz Matsui joined the Mets in 2004, with an impeccable track record. In Japan, he was a power-hitting shortstop, averaging 29 homers per season over his last four seasons. When the Mets got him, he was still only 28, theoretically in the prime of his career. In the three seasons since then, Matsui has hit 13 home runs. Rarely has $20 million been spent so ill.