The Italian is concerned his squad will struggle to cope with injuries and players leaving for the Africa Cup of Nations, and has ruled out selling any players.
When asked if he might consider investing in new faces, Mancini said: "Probably. We can't sell players. We don't have enough players to play if we sell players.
"We can have a problem because we lose three players and we have Micah Richards, I don't think he play until the end of February.
"Jack Rodwell - we don't know when he can play. Maybe we can recover Aleksandar Kolarov in two weeks. We will see this in next days."