This time, Dortmund has brought in Guirassy and also Maximilian Beier as fullkrug substitutes for next season and I think they will be quite a dangerous duo on Dortmund front line in the future, So far we haven't seen any rumors linking Sebastian Haller to other team, but if he capable Maintaining his performance next season of course Dortmund is just waiting for the time to sell him, currently he has a market price of around 12 million euros so that when an offer comes in which is greater than the market value then Dortmund will not think twice about letting him go next seasons.
Seeing from what is happening now, actually what Nuri Sahin is doing is a good thing, especially when they make some improvements to their attack line by bringing in Guirassy and Maximilian Beier, who in fact are quite young players and still have good potential even though it cannot be denied that at this time Guirassy will be hampered to play with Dortmund due to the knee injury he suffered but his potential is still quite good if you see the performance at the previous club.
For this season, Nuri Sahin seems to want to prove that even though he is a new coach but he is able to make a difference and give the best for Dortmund especially in competition. It's just that we just have to keep waiting for how the proof is done because surely it's not just Nuri Sahin who does that but some young and new coaches will also do the same.