Cahill has impressed greatly since arriving at the Reebok Stadium from Aston Villa in 2008, and his form at the heart of the Lancashire side's defence has seen the 25-year-old force his way into the England set-up, and attract interest from several of the Premier League's biggest clubs.
But Coyle has revealed his club are yet to receive a former offer for the Sheffield-born defender, despite widespread speculation linking him with a move to Arsenal, Tottenham Hotspur and Manchester City.
"Gary has been the subject of speculation every day, probably to the point he is frustrated by it," Coyle told Sky Sports.
"I have been very open. Some of the elite clubs in this country have noted their interest.
"But there has been nothing concrete. Until that changes, Gary is a Bolton player."
The 6ft 2in defender has played more than 100 matches since moving to Bolton, winning the club's Players' Player of the Year award in 2009.
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