The Ivorian midfielder – who only trailed Liverpool’s Daniel Sturridge and Luis Suarez in the Premier League scoring charts last season – is understood to have grown frustrated with life at the Etihad Stadium, and is angered by recent problems between himself and the champions’ hierarchy.
Toure is believed to have had a request to avoid a post-season friendly in favour of spending time with his now deceased brother turned down and was also involved in a run-in with the Sky Blues after they failed to acknowledge is 31st birthday.
Paris Saint-Germain are widely seen as favourites to snap up the African superstar, but United and Chelsea are also in the fight.
City are unlikely to be willing to offload their man, but if he pushes for a move it make sense for them to sell him while they can still fetch a respectable fee for his signature.
Toure has previously hinted at a desire to play for PSG, who are one of the few teams on the planet able to fund his wages.