The Nerazzurri have been persuing the Brazilian for some time, and Moratti insists the deal could still be done in the summer.
"This is a transfer that is not possible to do now," Moratti told reporters. "I think it will be easier to do next June. It's not an economic problem, but it's related to the player’s commitment to Corinthians."
Paulinho was part of the Corinthians team that won the World Club Cup in December. He has played eight times for the Brazil national team.
Inter finds itself in fourth place in Serie A, nine points behind league-leading Juventus, and it appears as though the Nerazurri will to have to climb the table without integrating Paulinho into the squad.