Gardner finished the 2005 season in the New York–Penn League season ranking 5th in at bats (with 282), 2nd in runs (62), and 5th in stolen bases (19). He was a Florida State League All Star in 2006, batting .323 in 63 games with 22 RBIs with the Tampa Yankees. He was third in the Florida State League in batting average and led the league in stolen bases with 30. Gardner also was second in the league in walks with 47.