Bill Mueller

William Richard Mueller ( ; born March 17, 1971) is an American former professional baseball third baseman who played in Major League Baseball (MLB). Mueller's MLB playing career was spent with the San Francisco Giants (1996–2000, 2002), Chicago Cubs (2001–2002), Boston Red Sox (2003–2005), and Los Angeles Dodgers (2006). Many of Mueller's accolades came during the 2003 season, when he won the American League batting title and a Silver Slugger Award.

A switch hitter, he became the only player in major league history to hit one grand slam from both sides of the plate in the same game on July 29, 2003. Mueller was the starting third baseman for the Red Sox' 2004 World Series championship team that beat the St. Louis Cardinals. Since his playing career, he has served in MLB as a front office assistant and hitting coach.