Frank Anthony Castillo (April 1, 1969 – July 28, 2013) was an American Major League Baseball starting pitcher. Castillo played for the Chicago Cubs (1991-1997), Colorado Rockies (1997), Detroit Tigers (1998), Toronto Blue Jays (2000), Boston Red Sox (2001-2002, 2004), and Florida Marlins (2005). A sixth round pick by the Cubs in the 1987 amateur draft, Castillo made his major league debut in 1991.