Hans-Joachim Watzke has said he's "very grateful" to Bayern Munich for their professionalism in allowing Mats Hummels to rejoin their rivals this summer.
Hummels left the Westfalenstadion to join Bayern in 2016 but rejoined the Black and Yellows in June. Dortmund chief executive officer Watzke told DPA (h/t Goal's Daniel Lewis) he found it "extraordinary" Die Roten were willing to let their defender leave.
The 60-year-old said: "I am very grateful to Karl-Heinz Rummenigge for having respected the player's will. I thought that was extraordinary. The way in which these negotiations ended was an indication to me how respectfully we are working together at the highest levels.