William Radhames Castro Checo (born March 29, 1952) is a Dominican former professional baseball pitcher and former pitching coach for the Milwaukee Brewers of both the American League and National League. He was the interim pitching coach with the Baltimore Orioles of the American League. Gary Thorne of MASN reported in the broadcast of the August 27, 2013 game between the Orioles and the Boston Red Sox that Castro succeeded Rick Adair because Adair had taken a leave of absence for personal reasons starting in August 2013. Gary Thorne, broadcasting the game between the Orioles and the Los Angeles Angels on July 5, 2012, on MASN, announced that Castro became unavailable for that game because of a death in his family and returned home to the Dominican Republic.
The longest-serving member of the Brewers' coaching staff, Castro was named bullpen coach in 1992 by rookie managerPhil Garner. Late in the 2002 season, Castro also briefly served as pitching coach after the resignation of Dave Stewart. He then returned to his bullpen role until he was named pitching coach by new Milwaukee manager Ken Macha on November 7, 2008. The 2009 season marked Castro's 18th consecutive season as a Brewer coach. Castro was subsequently fired as pitching coach on August 12, 2009, and replaced with former Brewer Chris Bosio.