The France international is ready to consider his options now that Euro 2012 is over.
Garcia has confirmed his right-back wants to depart, with Newcastle United and Inter Milan at the front of the queue.
Rudi Garcia: "Mathieu wants to go.
"But we do not have a plan for him to leave, he will not go unless I find a replacement of the same level.
"And he is a international player, he will cost - we will need to bring in a right-sided player of the same calibre and that requires a lot of money.
"If we find that, it will cost and we will have to pay that.
"Mathieu is one of my leaders, one of my major players and he is an example to follow.
"I understand his desire to leave, but we must find a replacement - my role is not to put my team in jeopardy."