German champions Borussia Dortmund today signed promising teenaged midfielder Leonardo Bittencourt from second division side Energie Cottbus. Bittencourt, who will turn 18 later this month, has signed for Dortmund for the 2012/13 season. He has German-Brazilian parents and has played for Germany at U-19 level. He has made 15 appearances, scoring two goals, in the second division this season and the transfer deal is thought to be around €3m.