Ian Maatsen left Chelsea for Borussia Dortmund in the January transfer window. The defender joined Dortmund on loan for the second half of the season and is absolutely thriving there. Since arriving at Signal Iduna Park, Ian Maatsen has made 10 starts in the Bundesliga, scored one goal and provided two assists. Under Mauricio Pochettino this term, the left-back only made one start in the Premier League, so things are obviously going much better for him in Germany. Maatsen has now not ruled out signing for Dortmund permanently when his loan finishes at the end of the season. Ian Maatsen explain…