Scottish champions Celtic are thought to be weighing up a move for Finnbogason as they look to bring in a striker to help fill the void left by Gary Hooper's departure to Norwich.
Celtic are thought to have watched Finnbogason score in Heerenveen's 2-0 win over NAC Breda on Saturday, while a number of other clubs are also thought to be keeping tabs on the Icelandic international.
Heerenveen sporting director Gaston Sporre admits they will listen to offers for Finnbogason, but that it would have to be a big fee to sell him.
"He's good for at least 20 goals a season for us and we won't sell him for a reduced fee," said Sporre.
"If we get a concrete offer for him we will negotiate, but our aim is to keep him here at Heerenveen. He hasn't told us he is unhappy or asked for a transfer. We will wait and see."
Heereveen coach Marco van Basten also claimed it would take a lot of money to prise Finnbogason away from the club.
"I do not want to sell him but I know my place and I know I am not the boss at Heerenveen," said Van Basten.
"If some club comes in with a large offer, there is nothing I can do.
"He's so important to this club on and off the pitch, so if clubs want to buy him, they will have to throw a lot of money at us."