Chelsea have long been linked with a move for the 26-year-old, who is out of contract at the end of the season.
Coyle said: “There has been a fee agreed between the clubs and we have now given Gary’s representatives permission to speak to Chelsea.”
Coyle added: “That is where we are with it. We obviously have a game tomorrow [against Wolves on New Year’s Eve].
“I have said to Gary that he has to be focused on giving everything for Bolton Wanderers, because he knows Bolton Wanderers has been terrific for him just as much as Gary has been for us.
“That is why [players] have representatives – to sort that out. Whatever 1 January brings it will bring.”
