Celta signed the defender two years ago from Barcelona, with the deal including 50 per cent of any sell-on fee.
However, Garces says they now want to secure 100 per cent of Mingueza's rights.
He stated: "Barcelona does not have the option to buy him back , it has a fifty per cent stake in a possible subsequent sale. I have met with the player's representative and with Mingueza and we know that his intention is to stay here and our intention is for him to stay."
Mingueza himself, recently told Marca: "I have things very clear, I know what I want and right now it is to be at Celta and have a very good season on an individual and collective level. The coach and the board know what I want, I have things very clear. I am focused on having a good year with Celta."