
Cottbus, bottom of the German league without a win this season, said the 54-year-old coach had signed a two-year contract.
"We are very pleased to have an experienced trainer and renowned expert under contract," club president Ulrich Lepsch said.
Prasnikar, a former Slovenia national team coach, will start with a home game Saturday against Eintracht Frankfurt.
Sander last weekend became the first managerial casualty of the new Bundesliga season after his side lost 2-1 at home to VfL Wolfsburg.
Reserve team trainer Heiko Weber was in charge for Wednesday's 5-0 defeat at Bayern Munich which leaves Cottbus on two points, three points adrift of second-from-bottom Nuremberg.
DPA