The Trotters defender continues to draw admiring glances from afar, with Arsenal reported to be among those keeping a close eye on his situation at The Reebok.
Coyle acknowledges that he could cash in on the 24-year-old and generate some much-needed finds, but feels he would be foolish to part with a player of such talent.
The Scot believes Cahill has the ability to grace the very top of the game, but hopes he will stick around with the Trotters for some time yet.
"Gary could play for anyone, with his pace, power and threat at set-pieces," said Coyle. "He wants to be the best player he can be and that is something I like in a player."
Keeping Cahill will be crucial to Bolton's plans going forward, with expectations around the club having risen again under Coyle's guidance.
Those within the camp believe European qualification is not out of the question in the near future, with club captain Kevin Davies among those setting high standards.
"We want to get into the top 10 this season," he said. "With the top six or eight teams spending loads, it will be difficult, but Fulham proved they could do it last season so we must look at them as role models.
"We've got everything in place here now to do that."