As reported by Bild, Mats Hummels admitted that the decision of Borussia Dortmund not to extend him was communicated to him through the media. The former BVB defender said that the information was leaked to the media before he even knew about it:
"Actually, it is supposed to be announced in a personal conversation. Someone wanted to get back at me for the interview (before Real Madrid) and leaked it to the press before I was told."Mats Hummels
According to information from Bild, the person who leaked the news is not one of the current BVB bosses; therefore, it is still unclear who was responsible for the leak. It is also indeed such an unfortunate way for Hummels to find out about his dismissal, especially for a club legend like himself.
Mats Hummels was unfairly let go by Borussia Dortmund. The German international was arguably Dortmund's best player in the campaign that led the Black and Yellows to the Champions League Final, but BVB was also a team with depth problems at defense during the 2024/2025 season. In that scenario, BVB could definitely have offered Mats a final contract, as he retired at the end of this season.
However, the leak was not the club's fault since they planned to have a personal conversation with Hummels to communicate him on their decision. In any case, it would be important to identify and punish the person who leak that information to the media. It was, again, an unfortunate way to say goodbye to one of the best defenders in club's history.