"I didn't get the feeling that we are at the stage where we can reach an agreement," Koulibaly's agent said.
"Right now though, our coach is Mancini and out of respect for him and his work, it is not up to me to speak about another manager," Zanetti said.
Roma will be watching their prospective Champions League playoff opponents with interest, as reaching the tournament is crucial to their season.
Monday's International Champions Cup game, Man United vs. Man City in Beijing, has been cancelled, while Tony Adams turns down Arsenal role.
Manchester City and Napoli are tracking Swansea forward Andre Ayew, sources close to the player have told ESPN FC.
Inter Milan's sporting director Piero Ausilio has confirmed that there has been contact with Napoli over Mauro Icardi.