The 25-year-old has long been tipped to leave the Reebok Stadium this summer, with Arsenal boss Arsene Wenger a known admirer. Manchester City were also heavily linked with the former Aston Villa star, although Roberto Mancini's interest does appear to have cooled.
And whilst Coyle would love the England defender to stay, he is realistic enough to know what will happen once a suitable offer is received. The Trotters chief said: "If someone comes in with the right deal for Gary and the club, he would go with our blessing."
He added: "He wants to play Champions League football and there has been unbelievable speculation regarding him.
"There have been elite clubs who have noted their interest. It is up to them to take that forward.
"They need to make a concrete bid so the club can look at it, otherwise there is nothing to talk about. That is the frustrating bit.
"We don't want to lose him. Until such time as we have an offer to consider, we must focus on Bolton."
Coyle insists the uncertainty surrounding Cahill is not having a negative effect on his own transfer plans.
He added: "I don't have two lists of targets; one if Gary goes, the other if he stays. I have one, the players I believe can take this club forward."
Source: PA
Source: PA