Borussia Dortmund has fired technical director Sven Mislintat after nine months as the club seeks to turn around a season which has seen last season’s Champions League runner-up fall to 11th in the Bundesliga. Mislintat, who previously worked at Arsenal and Ajax, was appointed in May to oversee “squad planning” at Dortmund. The troubled team fired coach Nuri Sahin last month and replaced him with Niko Kovac.