Boyata is back at City after they cut short his loan stay at Dutch side FC Twente earlier this month.
City called back the Belgian as he was not playing on a regular basis for Twente and they admitted they may loan him out again so that he can play first-team football.
The news has alerted a number of clubs to the 22-year-old's availability in this month's transfer window.
Nottingham Forest are thought to have enquired about Boyata as Alex McLeish looks to reshuffle his pack at the City Ground after recently taking over from Sean O'Driscoll.
Bolton have also asked about re-signing Boyata after he enjoyed a spell last season on loan at the Reebok Stadium.