|Date of birth||23 September 1969|
|Place of birth||Dumitra, Romania|
|Height||1.82 m (6 ft 0 in)|
|* Senior club appearances and goals counted for the domestic league only.
† Appearances (Goals).
Poschner was born in Dumitra, Romania. At the age of five, his family fled the country to escape the communist regime and moved abroad to Bietigheim-Bissingen, Germany. He began his professional career in 1987–88 with VfB Stuttgart, where he played three seasons with little impact in the first team (an average of 15 Bundesliga appearances).
Poschner emerged as a top flight player with Borussia Dortmund, scoring 14 league goals from 1990–94 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 lowly S.S.C. Venezia in January 1999.
Subsequently Poschner played with Rayo Vallecano, SK Rapid Wien, Polideportivo Ejido and TSV 1860 München, before retiring at the age of almost 35. In the 1999–2000 season he helped Madrid's Rayo to its best-ever classification in La Liga (ninth), and the club was eventually awarded a place in European competition via the Fair Play award, after which it reached the quarterfinals, with the midfielder being an important element.
- DFB-Pokal: 1996–97
- UEFA Cup: Runner-up 1988–89
- UEFA Cup Winners' Cup: Runner-up 1997–98
- DFB-Ligapokal: Runner-up 1997, 1998
- Borussia Dortmund