The Serbian international is unhappy with boss Manuel Pellegrini after being snubbed on numerous occasions this season with Gael Clichy the clear number one for the left back spot.
Former boss Roberto Mancini regularly switched full backs in his time at the Etihad, but Pellegrini is set on Clichy being his number one and Kolarov is now contemplating his future.
Inter Milan are interested in taking the 28 year old on loan until the end of the season, with a view to a permanent deal in the summer.
Former club Lazio and high flying Napoli have also been linked with Kolarov who enjoyed a successful three years in Serie A before his switch to England with City.
City are unlikely to want to let Kolarov leave, especially with a lack of cover in that position, and so a big money move would be the only thing that entices them into a winter deal.