The former Chelsea defender is being linked with Tottenham.
Mourinho said: "With him there are no problems or doubts. We have made that decision because I have known him since he was a child and he was not born to be a replacement. He is too good and with too much self-worth to be a replacement.
"The best solution for the end of his career is to find a club in an important league and that we try to find a club in an important league and we are trying to find a good solution for him and for us. If we reach the end of August and there is no conclusion he will be our player and we will be delighted with that."