Timothy Joseph Leiper (born July 19, 1966, at Whittier, California) is an American professional baseball coach and manager. In 2013, he will serve as a senior advisor for minor league operations for the Toronto Blue Jays of Major League Baseball.
Leiper, a former outfielder, had a 12-season (1985–1996) minor league playing career in the farm systems of the Detroit Tigers, Pittsburgh Pirates, New York Mets and Kansas City Royals, batting .273 with 40 home runs in 1,166 games and 3,910 at bats. He batted left-handed, threw right-handed, stood 5 foot, 11 inches (1.8 m) tall and weighed 175 pounds (79 kg).
His coaching career began while he was still an active player: he spent part of the 1992 season as an assistant baseball coach for North Carolina State University. In 1996, Leiper became a coach in the professional ranks, in the Mets' organization. He moved up to managing in 2000 in the Montréal Expos' organization, working at the Short Season-A and Class A levels before his promotion to the Triple-A Ottawa Lynx of the International League in 2002. After Leiper guided the Lynx to 80 wins in 143 games that season, he spent one season as pilot of the Class A Sarasota Red Sox before returning to the Lynx in 2004, who were by then the Triple-A affiliate of the Baltimore Orioles. Leiper then spent four seasons in the Pirates' system, including three as skipper of the Double-A Altoona Curve, before joining the Florida Marlins in 2009. In 2010, he managed the Jacksonville Suns, the Marlins' Double-A affiliate, where he led them to the 2010 Southern League championship. He then served as the Marlins' roving minor league defensive coordinator in 2011 and 2012
Internationally, Leiper played in Los Mochis of the Mexican Pacific Winter League in 1993, and Aguilas Cibanes in 1996, where his team won the Dominican League Championship. Coaching Internationally, In 1999–2000 He worked for Pastora, in the Venezuelan Winter League, as well as Aguilas, in 2007–2008 in the Dominican winter league. Aguilas won both the Dominican Championship and the Caribbean World Series.
Previously an offseason resident of Ottawa, Leiper has also been a coach on the 2004 Canadian Olympic team, and Canada's 2006 and 2009 World Baseball Classic squads. He was also a part of the Baseball Canada Staff that won bronze medals at both the 2008 and 2011 Baseball World Cups and the Gold Medal in the 2011 Pan-American games.
See also 
- Baseball at the 2004 Summer Olympics – Team squads
- 2006 World Baseball Classic rosters
- 2009 World Baseball Classic rosters
- Baseball Reference
- Boston Red Sox 2003 Media Guide, pp. 400-401
- Baseball America 2009 Directory
- Baseball America, February 22-March 10, 2010, page 56
- Baseball Canada