Before coming to
Duisburg, Hollmann was in the youth section of
Eintracht Duisburg. He played from 1970 to 1984 for
Rot-Weiß Oberhausen and
Eintracht Braunschweig in 350 games in the
Bundesliga scoring 33 goals. He took part in the
1972 Summer Olympics in
Munich. In 1977, Hollmann was playing for Bundesliga side Eintracht Braunschweig against
1. FC Kaiserslautern. When protesting against a penalty kick he thought it was not justified, the referee unintentionally knocked him unconscious, and Hollmann woke up in the ambulance. ==Coaching career==