The 23-year-old has been linked with a move to the seven-time European champions throughout the summer after a stellar 2011-12 campaign at La Mosson, in which he led his side to a shock Ligue 1 triumph.
Yanga-Mbiwa has insisted that despite his pledge to remain focused while at the club, if no approach is made this summer, he will move on at the end of the current campaign.
"You cannot say no to Milan. Until now, there has been no agreement and I am at Montpellier," the Bangui-born centre-back was quoted as saying by Telefoot.
"But we do not know what will happen in the last days of the transfer period. We will have to stay focused. In life you have to trust yourself.
"If the transfer is not for this year, it will be for next year."
The champions host Olympique de Marseille in Ligue 1 action on Sunday, with kick-off scheduled at 17.00CET.