You have to consider what they would cost to replace.
Also if we need to sell... there is no suggestion we do at the moment?
Would you sell Allan McGregor for 500k knowing it would cost us 20 times that to replace him if we were to buy a decent quality replacement?
The length of their contracts also dictates their value.
Presuming we aren't choking to sell them:
McGregor, age taken into consideration, why would we sell him for any less than 7-8 million?
Taverniers leadership and form speaks for itself, he is in good shape and has plenty of years left in him, I'd expect between 19 million for him.
Helander is a reliable international, doesn't cement his place in our squad however, reliable but not irreplaceable, 11 million.
Goldson is our vice captain and it shows, leads on the pitch, gets goals, defends well, and would be very difficult to replace. 15 million plus.
Hagi has still not completely proven his worth IMO, very decent prospect and on his day is an excellent player, international, 8 million.
Ryan Jack, injuries and competition for places in the midfield would drag his potential value down, but still a very reliable player who I would rather have in our squad, around 7 million.
Defoe - old, but does a job, contract is out but in the event of a new contact I'd still expect a couple of million if someone wanted to take him off of us.
Steven Davis - another player we would struggle to replace who has been incredible this season. Think about the resources we would have to plough into replacing him, I'd still want 7 million+ for him.
Ryan Kent - we won't get another winger as good as him without some very shrewd scouting or paying out a lot of money, starting point for me would be 25 million.
Patterson will only improve, currently I'd expect around 9 million to let him go.
Aribo, form speaks for itself, young international who will only improve, 10 million.
Kamara, very reliable international player who does a lot of the donkey work and we would notice his absence massively, 12 million would be the starting point.
Morelos, if we really want to cash in on him we should do it when he is in form, on his day he is great but he has spells of inconsistency. 19 million.
Roofe, great game recently but seems to struggle with injury, value could go up, based on what he has done so far I'd want around 8 million.
Barisic - reliable international, one of the best LBs in the country, would not be easy to replace, 20 million.