Kagawa, 23, has only a year left on his contract and has signalled his intent to move to the Premier League this summer, with Manchester United seemingly leading the race for his services.
However, given that Bayern Munich paid Schalke €22 million for Manuel Neuer last year when his contract had 12 months remaining, Dortmund are confident they can secure a significant fee.
“We all know the abilities of Shinji, his youth and the value he adds to this side,” Watzke told Sport Bild. “I also note what Bayern Munich paid for goalkeeper Manuel Neuer. He also only had a year left on his contract. Given those facts we can certainly expect a princely sum for him.”