Weigl joined Dortmund at the beginning of the season for a fee of just 2.5 million euros and has proven to be the season 's best bargain .
Weigl primarily plays as a defensive midfielder .
Weigl , who primarily plays as a defensive midfielder , joined Dortmund at the beginning of the season for a fee of just 2.5 million euros and has proven to be the season 's best bargain .