According to reporter André Hernan, if Manchester City needs it, they can recall Rez from Girona at any time.
André Hernan wrote on social media: "It has been finalized: Rez will be loaned to Girona for more playing time, and the defender hopes to gain a place in the national team through his performance in La Liga."
"Gerona promises to build a highly competitive team this season. There is such a provision in Rez's loan contract that players will return immediately if Manchester City needs it."