 In that second season in the Hanseatic city he also featured for the reserve squad, in Regionalliga Nord; 2002–03 had already been totally lost to an anterior cruciate ligament injury.In late January 2004, Friedrich returned to Mainz, still contributing with 17 matches "en route" to top level promotion.On 23 May he scored one of four goals in the league, netting the second in the decisive 3–0 home win against SV Eintracht Trier 05 on the final day of the campaign (promotion attained on goal difference).