Over the next two seasons, Zimmermann only made eighteen appearances for the Hertha first team, and in 1995 he crossed the city to join Union Berlin, of the Regionalliga Nordost.
A year later he signed for LR Ahlen, an ambitious team in the Regionalliga West, and helped them to promotion to the second tier in 2000, after a playoff victory over his old club Union Berlin.
He then spent a season each with Rot-Weiss Essen and SC Paderborn in the Regionalliga Nord, but only made a total of 33 appearances, due in part to injury.
However, this was only to last a month: Zimmermann didn't have the correct coaching licences, and as the club were unable to get special dispensation from the Deutsche Fußball Liga, he was replaced by Christian Hock.
In summer 2011, Zimmermann was appointed coach of the under-19 team of FC Ingolstadt 04, where he spent just over a year for leaving for personal reasons.