Masahiro Tanaka allowed Sho Nakata's two-run homer in the first inning of the pitcher's return to Japanese baseball, a 4-1 loss for the Tohoku Rakuten Golden Eagles to the Hokkaido Nippon Ham Fighters at the Tokyo Dome on Saturday.
The 32-year-old right-hander signed with the Pacific League club in January after completing a $155 million, seven-year contract with the New York Yankees.
Tanaka (0-1) allowed three runs and four hits in five innings with five strikeouts and a walk. He also gave up Kazunari Ishii's home run in the second.
The defeat ended Tanaka's 28-game regular-season winning streak in Japan.