Bundesliga leaders Borussia Dortmund have been dealt an injury blow with the news that in-form midfielder Shinji Kagawa could be out for several weeks. The Japan international, who has scored seven goals this season after spending over six months out with a broken foot, has suffered torn ankle ligaments. Coach Jurgen Klopp told a press conference today that the injury, which the 22-year-old picked up in training yesterday, is likely to keep him out for at least a fortnight. \"It seems like he suffered the injury during a challenge in training on Wednesday,\" said Klopp. It did not look too bad to begin with, but then it swelled up quickly. I don\'t see any chance of him playing against Hertha Berlin and Hannover. (Club doctor) Dr Markus Braun says we should be looking for him to return in the Mainz game.\" Kagawa had only just returned to his best form a year after breaking his foot while on international duty, scoring three goals in Dortmund\'s last three games.