Feyenoord have urged Aston Villa to make a decision on whether the club will press ahead with plans to sign their captain Ron Vlaar.
The Netherlands international travelled to Birmingham last weekend and held talks with Villa boss Paul Lambert regarding a move to the Premier League.
Vlaar subsequently admitted it would be a 'dream come true' to join Villa, but neither the defender nor Feyenoord have received any further contact.
The Eredivisie side's technical director Martin van Geel believes it is unfair of Villa not to have made a decision on signing the 27-year-old.
"If I was Ron, I would set a deadline," Van Geel told the Dutch media. "I understand that his agent will do that.
"Ron has to know where he stands, and so do we. This isn't fair, especially towards Ron.
"As a club I think you are morally obliged to show clarity towards a proposed new player. Now, it's only confusing, not just for us, but also for Ron."
Feyenoord coach Ronaldo Koeman added to NUsport: "It is good when you invite a player and give him a positive feeling but it seems to me that then you need to try a direct transfer and complete it if you want the player.
"They have so much money but they do not pay for him.
"I need to gradually know where I stand. If it can't be guaranteed that Ron continues here then in the final friendly matches I will play without him in the centre of the defence."