The 28-year-old's future at the Etihad Stadium has been called into question on a number of occasions due to his failure to cement a regular first-team spot.
According to Dejan Joksimovic, who is the assistant to Kolarov's agent, Roma and Juventus are among the clubs interested in the player, but wages could prove to be a stumbling block.
"I can tell you that maybe Roma is following him, but there are some problems," Joksimovic told Calciomercatonews. "First he has a contract worth £2.8m for another year with Manchester City, so it would be difficult because Roma cannot pay these figures.
"There are other teams that are following him like AC Milan, Juventus, Inter Milan, Monaco and also some of the Russian teams that are now willing to pay outrageous sums. So for now we do not know anything and there is nothing concrete."
The Serbia international joined City from Lazio in 2010.