The Trotters have agreed a fee with Chelsea for their England defender and it was anticipated the transfer would have gone through early this week.
Cahill remains a Bolton player amid rumours Chelsea manager Andre Villas-Boas is getting increasingly frustrated. Coyle said: "Gary is a Bolton player and until I hear something different in terms of negotiations being concluded between both parties, he will be in line to play against Manchester United."
He added: "Dialogue continues between Gary's agent and Chelsea."
"We accept it has probably been long-drawn. It is over two weeks ago that we agreed a fee.
"But sometimes that is the nature of football business. It can take that period of time."
It has been suggested rival suitors have made their interest in Cahill known. However, this is news to Coyle, who insisted Chelsea remain the only current option for Cahill.
"If other clubs are linked with him it is just speculation," he said. "We have agreed a fee with Chelsea. I have had no dialogue with any other club.
"We recognise it is the silly season but I don't deal in rumour. I only deal in fact.
"The fact is we have agreed a fee with Chelsea. We have not spoken to anyone else. That is where we are."