Dortmund are preparing for Guirassy move which would be really good to strengthen their scoring skills. However there are already 3 centre-forwards in the squad.

Füllkrug is a new transfer you know and he played really well in his first season. Together with Malen on the wing they made a really good goal contribution in total. However maybe Dortmund wants an even more productive striker like Guirassy in Füllkrug's place. When it comes to Haller he has been facing injury problems quite often so I don't feel like he has a bright future with this team anymore. Maybe he might even leave this summer.
Other than that Dortmund should work on signing some centre-backs too. Hummels is leaving and Niklas Süle has put on weight quite much recently.
