Kovacic has started on the bench for the Nerazzurri's last two Serie A games as well as the midweek Europa League draw with Celtic, but the coach has denied having an issue with the Croatia international, insisting he is merely being cautious with the 20-year-old's development.
"Mateo is a first-choice player, as are others," he told reporters on Sunday.
"He must be allowed to grow calmly and to be helped by experts, as he is the one on whom we will build the future of Inter.
"Kovacic is extraordinary. He works and he works. He only needs to understand some difficult tactical ideas that are hard for a 20-year-old, but he will have his opportunities.
"We are playing lots of games at the moment so we will definitely mix things up a bit against Cagliari. We have good players who are performing exceptionally well."
Mancini also says he retains the utmost belief in Lukas Podolski, even though the German is still waiting to score his first goal since arriving at Inter on loan from Arsenal during the winter transfer window.
"I hope Podolski is settling in well," the former Manchester City boss added.
"He is improving a lot on the pitch and I hope he can get the goal he needs as soon as possible."
Inter currently sit 11th in Serie A but can go as high as sixth with a victory over Cagliari on Monday.