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.
Füllkrug played very well in Dortmund last year in my opinion. Dortmund made a good profit by selling him for a good transfer fee. Now they bought young Beier instead and will sell him for a higher price. If he shines well for a year or two, Beier can earn Dortmund big money. Guirassy will give the impression of being the other goal scorer.
Dortmund's main business is to make money by selling the best players in their squad. They have done the same this season too. Sold Niclas Füllkrug, one of the most talented players in the squad, for 30 million. And now again the Dortmund management will invest this money in the purchase of young players.
Maximilian Beier and Sehrou Guirassy have been bought by Dortmund management this season. While Guirassy is 28, Beier is 21 years younger. I think the Dortmund management is planning to sell Sebastien Haller for a very high price next season. Haller is a very talented player. Selling Haller would also benefit the Dortmund management financially.
Losing star players is not something surprising for us to see so far in Dortmund, in the last few seasons we have seen Dortmund lose Haalaand, Sancho, Belingham and currently Fulkrug has also left for Westham, but as usual Dortmund will always have young talent and substitute players which can actually make them a team to be reckoned with so far in the Bundesliga, Fulkrug and Sebastian Haller have been their mainstay players last season and we can see how big the contribution of these two players was for Dortmund last season in their journey in the Champions League, but still that is will not guarantee that they will remain in Dortmund for a long time.
This season, 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.