The 24-year-old has been linked with a move to either the Premier League or Championship after turning down a new contract.
The 24-year-old has turned down a new four-year deal with the Scottish Premiership leaders (via Daily Record), which has seemingly alerted clubs south of the border as the Daily Mail reported that both Norwich City and Queens Park Rangers were monitoring his situation.
And their desire to land the Scotland international may well increase after hearing the asking price that the Hoops have set on a player who was once considered to be one of their brightest prospects.
The Daily Record reports that Forrest's value was around £5m four years ago amid speculation that Tottenham were interested. And while he has not kicked on in the way that many expected him to, being able to sign him for a fraction of that price is something that will surely appeal to the two clubs reportedly chasing his signature.
And while Celtic supporters may have previously been disappointed at the thought of losing Forrest for such a low fee, his inconsistent form - he has returned just two goals and one assist in the Premiership this term - and his decision to snub a new deal with the club that gave him his chance means that very few tears are likely to be shed if someone does offer the price that the Bhoys are now looking for.