Bundesliga side SC Fortuna Köln in 1998. After Fortuna were relegated in 2000, Schuler moved to 1. FSV Mainz 05 where manager Jürgen Klopp converted him from a winger to fullback.
Schuler was part of SC Fortuna Köln in the Bundesliga in 1998. Following Fortuna's relegation in 2000, he joined 1. FSV Mainz 05, where coach Jürgen Klopp repositioned him to play as a fullback from his original position as a winger.