After serving the youth system, Adler joined the B team in 2002. He made eight appearances for the B team in the 2002–03 season. At the beginning of the 2003–04 season he became part of the club's first team, which played in the Bundesliga. Nevertheless, he didn't make an appearance and continued to play for the second team. He also failed to make any first team appearances during the 2004–05 and 2005–06 seasons. However, in the 2005–06 Regionalliga season, he made 19 appearances for the B team. In May 2006 he sustained a rib craze, which led to a surgery in which his rib was strengthened. Because of his injury Adler had to pause until February 2007.