Adams was brought up to the major league club late in the 2004 season and had his official rookie season in 2005. He was used primarily in the lead-off position in the lineup. Adams finished the 2005 season with a .256 batting average, .325 OBP, 27 doubles, 5 triples, 8 home runs, and 11 stolen bases. Adams finished seventh in the AL in sacrifice flies and tenth in the American League in at bats per strikeout. Adams was named to the Topps Major League Rookie All-Star Team along with teammate Gustavo Chacín. However, he made 26 errors in the field for the Blue Jays and was often criticized for his throwing arm.