ブレバード・カウンティ・マナティーズ
Gillespie was drafted by the Milwaukee Brewers in the third round of the 2006 Major League Baseball Draft. After going pro in 2006, Gillespie played for their Rookie league Helena Brewers. He was promoted to the Class A-Advanced Brevard County Manatees in 2007. Gillespie spent the entire 2008 season with the Double-A Huntsville Stars. In 2009, he was promoted to the Triple-A Nashville Sounds.