When asked if players might be brought in, the City manager said: "Probably.
"We might have a problem. We lose three [to the African Nations Cup] and I don't think Micah Richards will play until the end of February.
January 2010: Former Arsenal defensive midfielder Patrick Vieira joined on a free transfer from Inter Milan and Middlesbrough winger Adam Johnson is signed for £7m January 2011: Bosnia striker Edin Dzeko is purchased from Wolfsburg for £27m January 2012: Mancini did not buy anyone "Jack [Rodwell] - we don't know. Maybe [Aleksandar] Kolarov can recover in two weeks. We will see."Because of his depleted squad, the Italian ruled out any outgoings.
"We can't sell players. We don't have enough players to play if we sell players," Mancini insisted.
The 48-year-old's words mark a change of course after assistant manager David Platt stated last week that he would be "surprised" if the Premier League champions did any business in the upcoming transfer window.
Mancini has bought the majority of his players in the summer since he took over at the club from Mark Hughes in December 2009, with now-Sunderland winger Adam Johnson and striker Edin Dzeko his only major purchases during January.
As well as being without right-back Richards, midfielder Rodwell and left-back Kolarov, right-back Maicon has been receiving treatment in Italy for a knee injury, while striker Mario Balotelli is not expected to return from a virus until next weekend.
The list of absentees has lengthened by the Africa Cup of Nations call-ups for Ivory Coast trio Yaya Toure, Kolo Toure and Abdul Razak. All three could be missing for up to five weeks from next weekend.
City have also chosen not to appeal the red card midfielder Samir Nasri received in the 4-3 victory at Norwich on Saturday. The 25-year-old will now definitely miss the New Year's Day home game against Stoke, the FA Cup third round tie against Watford and the return to his former club, Arsenal.
