Borussia Dortmund sporting director Sebastian Kehl expects defender Niklas Süle to significantly improve his performance in the coming weeks. “I think things are slowly starting to click,” Kehl told Sky on Sunday. “Of course, we had hoped for more, especially in the last few months. Niklas can do more and I expect that from him in the coming months.” Kehl has had many conversations with the 28-year-old. “He is very willing to work on it,” he said in response to repeated criticism of Süle’s size and fitness. Despite an illness for Mats Hummels, Süle was initially on the bench for Dortmund’s 3-0…