The 31-year-old was linked with a move to follow former boss Jose Mourinho to Real Madrid earlier this summer.
“Tomorrow we will start the preparation of the new contract”, Milito’s agent Fernando Hidalgo told Sky Italia.
“Then I’ll fly to Buenos Aires to allow Diego signing it. Everything is okay and next week I’ll be again back to Italy to give the contract to the Italian League.”
Milito’s current contract is set to expire in the summer of 2013.