Borussia Dortmund want to sign Ian Maatsen from Chelsea, but the German giants look to have hit a bit of a stumbling block. Ian Maatsen seems to be edging closer to the Chelsea exit door after being overlooked by Mauricio Pochettino this season. According to Sky Sports Germany, Dortmund are in talks with the Blues and the left-back over a potential deal. However, the same outlet has also claimed that it is still pending because Chelsea are insisting on a loan with an obligation to buy in the summer for €30m (£26m). Maatsen will be desperate for that to be ironed out, with the 21-year-old havin…