Reports in Spain suggest Zigic is stalling on a move to the Potteries whilst weighing up his options.
The new club is believed to be Blackburn Rovers.
"We were looking at a quick sale but now the situation has changed," Los Che vice-president Fernando Gomez told skysports.com.
"It is true another English club has asked about the player, but Valencia wants a sale and not a loan," added Gomez.