Tetsuya Yamaguchi is a Japanese Nippon Professional Baseball player with the Yomiuri Giants in Japan's Central League. He was playing in the Missoula Osprey before he was drafted by the Giants in 2005. He was awarded as Central League's Rookie of the Year in 2008, beating his teammate and another award favorite Hayato Sakamoto, by finishing with an 11-2 with 67 appearances, the most wins of all-time in Giants' relief pitchers. He was then selected to the National team playing in 2009 World Baseball Classic, being the only relief pitcher selected by the National team. 

November 11th, 1983 in Kanagawa-ku (Age 40)