Mancini, 46, has had to deal with claims of dressing-room dissent and in-fighting for most of this season but has managed to guide City into the Champions League for the first time in the club's history.
City are expected to spend big in the summer as Mancini assembles a squad he believes can compete at Europe's top table, though there remains a big question mark over Tevez and whether he will still be around to lead the team.
The Argentina striker's future has been in doubt ever since he handed in a transfer request last December, a request which he later withdrew. But while Mancini acknowledges his captain's role in City's success this season, the Italian boss says that if Tevez or any of his team-mates are unhapppy at Eastlands, they should leave.
"He's got a five-year contract but I always say that a player should stay here because he believes in the project and he's happy to stay at the club,'' Mancini said. "But if I'm not happy to stay at City I will leave. It's the same for the players.
"If they aren't happy to stay at the club it's better they leave. But this is not just for Carlos, it's for the players in general. When you start your job you should be happy because the season is long and there could be a thousand problems.
"I never said that Carlos wants to leave. I said it would be his decision. He has scored 22 goals and that's very important. We always say he's an important player for us. But we've got this far because all the players have contributed.''