Lescott has been linked with a move after being limited to just seven Premier League starts for the defending champions this season. The 30-year-old has slipped to fourth choice under Mancini, behind Vincent Kompany, Matija Nastasic and Kolo Toure despite being a regular in the England squad.
There have been reports Lescott's former club Everton, who reluctantly sold the player to City for £22 million in August 2009, would be interested in re-signing him when the window opens on New Year's Day. However, Mancini appeared to rule out Lescott leaving after claiming he could not afford to sell any players in January because of injuries and the absence of three players at the CAF Africa Cup of Nations.
Ivorian trio Kolo Toure, his brother Yaya and Abdul Razak are due to leave for the tournament, which begins in South Africa on 19 January after City's home game with Stoke City on Tuesday. In addition, the likes of defenders Maicon and Micah Richards remain sidelined along with midfielder Jack Rodwell.
And despite having one of the biggest and most expensive Premier League squads at his disposal, Mancini claims he cannot afford to allow Lescott, or anyone else, leave before the end of the season. "We can't sell players. We don't have enough players to play if we sell players," said Mancini at a press conference in Manchester on Monday.
City begin 2013 in second place in the table, seven points behind leaders Manchester United, whose manager Sir Alex Ferguson celebrated his 71st birthday on Monday. "My message to Sir Alex is happy birthday, congratulations because I think now they deserve to stay on the top," added Mancini. "Happy New Year to him and his family."
While Mancini paid his respects to Ferguson, he also insisted there is enough time for his side to make a successful defence of the title they won on the final day of last season. "2012 was a fantastic year for us but we chance to do a fantastic 2013," he added.
"We won a championship after many years. I think it was a fantastic season and I think we are happy for everyone that works for this club and all our supporters because they deserve to have a big moment. I hope the next year will be the same. If it is the same then for me it is okay."
Mancini also revealed City have yet to decide whether to appeal Samir Nasri's red card for a head-butt on Norwich's Sebastien Bassong at the weekend. "We will decide this morning. We talked yesterday and today we decide," Mancini said.
"We don't know what can happen if we appeal. Usually they reject an appeal. This could be a problem because after this game we lose three players to the African Cup of Nations."
Edin Dzeko is set to retain his place in the side against Stoke after scoring twice in the 4-3 win at Norwich after making a rare start. "If he scores two goals every game we don't have a problem," Mancini said. "I am happy for Edin because I think he deserves to score.
"He scored two goals but he did also a good performance. I hope he can continue to score and play well. Not only now, always Stoke are very difficult to beat because they are strong, they are tall, they fight on every ball."