Coyle feels the situation is not fair on the 25-year-old and wants it swiftly resolved.
"There had been tentative enquiries, but there has certainly not been firm offers," Coyle said.
"I have said to Gary that as soon as there are, then he will be the first to know. But I think a lot of the speculation is certainly unfair on him at this moment.
"We know they have the interest, but if somebody is going to back that up, then do it - put your bid in, or if you don't, leave the kid alone and let him get on with his football. I think that is only fair for everybody.
"If it is going to happen, then the sooner it does the better - if not, let the boy focus on his career, which to this point has been great and will get better.
"He is a young player, he is only going to improve and he is established in the England squad. He has been a revelation for me during my tenure here.
"But I think it is only fair that they either come and get him now or they let him concentrate on his football."