Roberto Mancini will resist any attempt by Tottenham boss Harry Redknapp to prise Micah Richards from the City of Manchester Stadium during the current transfer window.
City's close rivals for a top-four finish have been strongly linked with a move for 21-year-old Blues defender Richards, who has had to fight hard for a first-team place this season.
But new manager Mancini, who has been impressed by Richards in his hour of defensive need, insists that the player - who has 11 senior caps to his name - is a big part of his plans.
Waving aside the idea, City's boss said: "How could I afford to lose Micah? We have only four fit defenders at the moment! Anyway, I rate him very highly, he has played for England and has great potential for the future. It is important that he stays."
Richards, who came off after 55 minutes of last weekend's third-round FA Cup win at Middlesbrough, is expected to be fit for Monday night's home match against Blackburn Rovers.
Mancini, who was without nine of his stars at the Riverside and drafted in 19-year-old Dedryck Boyata, hopes to have Shaun Wright-Phillips and Roque Santa Cruz back in action for Rovers.
Both have returned to training, and though Wright-Phillips' ankle remains sore, he has a habit of making the cut on the day, while striker Santa Cruz is desperate to face his former club.
The Paraguay hit man, yet to make a start for his new manager, has overcome the calf injury that has ruled him out of three games since a two-goal performance in the 4-3 win over Sunderland.
Mancini said: "I think Shaun can recover. Both of them have a chance. It would be a big game for Rocky as Blackburn are his old club, but we will have to see if he is OK."
Santa Cruz is being linked with a bid from Espanyol, but Mancini said: "Roque is most important for us, and I do not want to lose him. He was injured for 15 days and we missed him. For me, he is important to the team."
Mancini, still without Wayne Bridge, Joleon Lescott and Nedum Onuoha, added: "We have problems at the back and in midfield, because Stephen (Ireland) is injured, but that is football and we have to get over the problems."