From 2007 through 2013, Tanaka played for the Tohoku Rakuten Golden Eagles in Nippon Professional Baseball's Pacific League. Tanaka was posted by the Eagles after the 2013 season to be signed by an American team; he agreed to terms with the New York Yankees and signed a seven-year, $155 million contract, the fifth-largest deal ever given to a pitcher at the time. Since the start of the 2014 season, Tanaka has accumulated a 66-35 win/loss record and a 3.56 lifetime ERA.

This Rawlings official MLB baseball was signed in blue by Tanaka and includes a JSA letter of authenticity. The signature is a bit smudged, as seen in photos.