Manchester United is among the clubs eyeing a move for the 22-year-old standout.
Anderlecht manager Hein Vanhaezebrouck has insisted that it will take something of an 'insane' offer to prize Leander Dendoncker away from the Constant Vanden Stock Stadium this month.
The 22-year-old is a marked man this transfer window and a number of clubs, including West Ham and Manchester United have been sniffing around.
Dendoncker has been on the scene since 2013 after rising up through the club's youth system, and has already made over 100 appearances for the club.
Vanhaezebrouck said of the highly rated defensive midfielder, as quoted by Tifo Football on Twitter: "He can only leave when an insane bid comes in. Over the next six months he has to show his very best level and then we can work towards a top transfer in the summer."
Some reports have claimed the Belgian outfit will listen to offers around the £26.5m mark, which would certainly be within United's budget if they felt the need to follow up their initial interest in the player.
While that figure may not seem 'insane,' it is undoubtedly a large fee for a young player coming from the Belgian First Division.
Mourinho supposedly made an enquiry over the star after he shone against the Red Devils in the sides' Europa League quarter-final clash last season. United went on to buy the more proven Nemanja Matic in the summer, but the Portuguese could go back in for Dendoncker this month.
Club captain Michael Carrick is likely to retire at the end of the season, and Ander Herrera has tailed off massively from the heights he hit performance-wise last term. Speculation also still surrounds the future of Marouane Fellaini, who is out of contract this summer.
Dendoncker has been filling in at center half recently for Anderlecht, and his versatility is definitely drawing attention to himself.