Poschner emerged as a top-flight player with Borussia Dortmund, scoring 14 league goals from 1990 to 1994 and losing, for the second time, the UEFA Cup. He returned to Stuttgart for four and a half additional campaigns, helping the side win the 1997 edition of the DFB-Pokal and moving to S.S.C. Venezia from Italy in January 1999; additionally, whilst with the former club, in the 1998 UEFA Cup Winners' Cup Final against Chelsea, he was sent off for dissent late on to put both teams down to ten men, with Dan Petrescu having been ejected beforehand in a 0–1 loss in Stockholm.