Roberto Mancini has said that Manchester City need to add to their squad in the January transfer window if they are to challenge for the Premier League title this season.
City currently enjoy a three-point lead at the top of the table as they chase their first title in 44 years.
"This could be a first title for many years and we need to do everything we can to win it," Mancini said.
City have spent £500m on players since August 2008 and concerns have been raised over financial fair play issues with the club.
When asked if he would have to sell before buying new players, Mancini said: "Yes, yes. This is the problem. But if we don't have the players, it's tough for us."
Manchester City will be without midfielder Yaya Toure and his brother Kolo throughout January while they are on African Cup of Nations duty.