Answer
The answer is no. Martin Harnik has never played as a central defender. He has primarily played as a winger or forward throughout his career. He began his professional career as a winger for Werder Bremen II in 2006 and has since played for several clubs, including VfB Stuttgart, Fortuna Düsseldorf, Hannover 96, and SV Darmstadt 98. He has also represented the Austrian national team as a winger or forward.