 Boateng made his first team debut in a 2–0 win against Eintracht Frankfurt in the second round of the 2005–06 Bundesliga season on 13 August 2005 at the Olympic Stadium, being brought on at the beginning of the second half.Boateng was awarded the "Fritz Walter Bronze Medal Award" in the Under-18 category in 2005.Boateng started his first Bundesliga match in a 2–2 draw against Borussia Mönchengladbach in the 14th round of the Bundesliga season.