Thorgan Hazard has told Borussia Monchengladbach he wants to leave the club and will not sign a contract extension.
Glabach sporting director Max Eberl confirmed on Monday the 26-year-old Belgium international has voiced a desire to purse a new challenge.
A report in German publication Kicker claims Borussia Dortmund are leading the race to sign the attacking midfielder, while Atletico Madrid and Liverpool have also been linked.
Hazard's contract runs until the end of next season and does not include a release clause, meaning potential suitors may have to stump up a hefty fee to convince Gladbach to sell.
"We made our intentions to extend Thorgan's contract clear a while back now, but he hasn't reciprocated that interest," Eberl said.
"He has now told us that he doesn't want to extend his contract and instead wants to take the next step in his career by leaving the club.
"However, he still has a contract with us until 2020 and there is no release clause.
"Interested parties have to offer us a transfer fee that recognises his worth as an exceptional Bundesliga forward and a regular feature in one of the best national teams in the world.
"If it ends up being the case that Thorgan leaves us, then we will do what we've done well in the last few years - we will take the money we make from the transfer and use it to buy more exciting players for our team."
Hazard, the younger brother of Chelsea star Eden, has scored nine Bundesliga goals and assisted as many this season after netting 10 times and laying on five in 2017-18.
He was part of the Belgium squad that reached the semi-finals of last year's World Cup, appearing in wins over England and Panama.