Tomohiro Nioka is a 31-year old shortstop for the Yomiuri Giants. Turns out he was not eligible for free agency this winter, though. I recently asked Bob Bavasi of JapanBall.com about Nioka; his reply is below.
Nioka, the Giants shortstop, missed a good chunk of the season in 2001 and 2004 because of injury. So, even though he has played in nine seasons, nine years being necessary to become a free agent, he lost too much time with injuries during those two years and, therefore, did not qualify. He should be able to file for free agency at the end of the 2008 season if he plays the full schedule.