Monaco vice-president Vadim Vasilyev says he won't hold Fabinho back from moving to a bigger club.
"He's one of the key players in our squad, a very regular player," said Vasilyev.
"He's very important, we can always count on. We are very happy that we managed to keep him. I think this is one player you want to keep forever.
"But we realise in Monaco we have a certain model, that at a certain moment when we feel it's right we have to let players go in order to be successful again. This is not only about money; this is more about being successful."
Asked if he expected Fabinho to stay in January, he said: "Yes, that's the idea of course. You never want to make any major changes in January, except something really extraordinary."
Vasilyev also confirmed that their was "strong" interest from both Manchester clubs for the Brazilian.
He added: "This is just normal. We just have to find the right time for each of them (players)."