Manager Peter Bosz has acknowledged that Kai Havertz is likely to leave Bayer Leverkusen at the end of the season.
Having already emerged as the club's star man at the age of 20, Havertz is being heavily linked with a move to a top European club.
Liverpool, Manchester United, Barcelona and Bayern Munich are all said to be in the mix, and Bosz has admitted that he would be surprised to see the playmaker remain at his current team for much longer.
Speaking to Algemeen Dagblad, Bosz said: "Kai is 20 years old, but this is already his fourth season in the Bundesliga.
"That says a lot. Everyone in Germany sees him as a child prodigy. He is from Aachen, has been here since he was eight. Nice boy to work with. Intelligent. He also plays the piano.
"We sold his buddy, Julian Brandt, to Borussia Dortmund last summer. Havertz suddenly became even more of an eye-catcher. "A lot came to him before the winter break. We lost the derby at Koln and three days later also at home to Hertha Berlin.
"He can't be held on to next summer. That will be a transfer of €100m (£90.75m). What am I saying? More than €100m."
Havertz has contributed nine goals and seven assists from 30 starts in the Bundesliga and European fixtures this season.