Colabello finished the 2015 regular season with career-highs in nearly every statistical category, including batting average (.321), hits (107), home runs (15), RBI (54), and on-base plus slugging (.886). He hit a solo home run in Game 5 of the 2015 American League Championship Series, which helped the Blue Jays top the Kansas City Royals on October 21 and force a Game 6.