Derek Shizuo Tatsuno (born 1958) is a former baseball pitcher.
Tatsuno attended the University of Hawaii at Manoa from 1977 to 1979 where he amassed an impressive record in collegiate baseball as a pitcher.
While in college he became the first 20-game winner in a season (in 22 starts) and threw 234 strikeouts (both national records).
Tatsuno was selected in the 2nd round of the regular phase of the June 1979 draft by the San Diego Padres. However, he signed a reported one million dollar contract to play in Japan. He was selected in the 2nd round of the January 1980 secondary phase by the Chicago White Sox, and in the 1st round of the January 1982 regular phase by the Milwaukee Brewers.
Tatsuno never played in the majors. In 1982 he played for the Brewers' AA affiliate, the El Paso Diablos of the Texas League, going 7-2 with a 6.42 ERA and walking more than a batter an inning. In 1983 he was demoted to the Single-A Stockton Ports of the California League, going 10-6, 3.24, but Milwaukee released him. After not pitching the two previous years, Tatsuno resurfaced briefly with the Hawaii Islanders of the Pacific Coast League, the 1986 Triple-A affiliate of the Pittsburgh Pirates and 1987 Triple-A affiliate of the Chicago White Sox. In 1986 he posted a 5.52 era in 29.1 innings over 11 games. In 1987 his marks raised to a 6.60 era in 43.2 innings over 22 games.