The loss of FullKrug who moved to Westham some time ago forced Dortmund to move quickly to find a replacement, especially now that Guirassy is still injured so with the new season will starting in a few days, Dortmund immediately brought in Maximilian Beier as their mainstay center forward next season,
Even Dortmund lost Füllkrug to Westham and he is an awesome player for the long term i think they have done all right with Beier.
It was not only the injury of Guirassy that they tried to get Beier as they already haved him on the list for some time.
But now its for sure the best way to have another good young and talented striker that can play when the season starts.