Iriki attended the Perfect Liberty High School and Asia University (Japan) before joining the Honda amateur baseball team.

In 1999, his older brother, Satoshi, was traded to the Giants from the Kintetsu Buffaloes, and the two were teammates from 1999 to 2000.

In the 2003 off-season, Iriki was traded to the Hokkaido Nippon-Ham Fighters, and caused some controversy by trying to make the team ensure that he would be released to play in the major leagues in two years.

On April 28, 2006, Iriki was suspended for 50 games for violating Major League Baseball's policy against performance-enhancing drug use.

Iriki was dropped by the Mets at the end of 2006, and spent the 2007 season in the Toronto Blue Jays minor league system.