The 21-year-old's form for the Canaries so far this season has resulted in interest from some of England's biggest clubs, Maddison scoring 15 goals on his way to being named the club's player of the year.
The Mirror reports that Norwich are ready to cash in on the midfielder too, placing a £30m asking price on his head.
Maddison - an England Under-21 international - spent last season on loan at Aberdeen but has since established himself as one of Norwich's key players, appearing in all but two of their Championship outings this season.
In addition to scoring 15 goals across all competitions, Maddison has also laid on eight more for his teammates this term.
Norwich could also lose winger Josh Murphy this summer, with the likes of Swansea City, Leicester City and Crystal Palace rumoured to be interested in the 11-goal forward.