A host of top European sides are reportedly keen to snap up the English defender, who is available to talk to clubs from January.
Throughout the summer the 25-year-old was continually linked with a switch to Chelsea and Arsenal, whilst Juventus were also rumoured to be considering a move for the defender.
Cahill told Sky Sports News: "There's no disguising the fact I am out of contract at the end of the season, so there will always be speculation.
"For me, it's just a matter of keeping focused and playing football and trying to play at the top of my game.
"Nobody has a crystal ball so no-one has a clue what will happen.
"I am contracted to Bolton and they have been fantastic. I will deal with whatever is in front of me if and when it arrives."