The agent of Curtis Davies admits West Brom will demand a huge fee for the defender.
Tottenham are still waiting in the wings, provided they can offload one of their glut of central defenders, says the Sunday Mercury.
"Curtis is the most valuable asset the club have. The only thing that's worth more than him to them is the ground - he's the jewel in the crown.
"But he wants to be a Premiership footballer and he feels that he's a victim of circumstance who is being held to ransom."
Davies is known to be frustrated that Kamara has now departed, even though he put in a transfer request days before the striker - both of which were rejected.
Sproson fears there will be more weeks of waiting for the former Luton centre-half unless Albion grant Davies's wishes and publicly state what price they will accept.
"At the meeting I had with Jeremy when Curtis was present he wouldn't put a figure on his head," said Sproson.
"He's within his rights to wait until somebody comes in and makes him and offer.
"People have mentioned £9m but Curtis will be there until he's 74 if they expect to get that.
"Maybe that's what Jeremy wants. He doesn't want to lose his best player but what's the point of keeping him if he's not happy?"