Tevez scored City's winner against Bolton, but his seventh goal of the season and an impressive performance wasn't enough to keep him on the field.
A City insider told The Sun: "Carlos isn't happy he keeps getting taken off.
"He wasn't tired against Bolton and was playing well, so didn't see why he should be replaced. It has been happening all season and he cannot understand why Mancini keeps doing it to him."
Tevez is the second most-substituted player in the Premier League this season, behind only Bolton's Johan Elmander.But Mancini doesn't think there's an issue: "It is not a big thing. I am happy when one player doesn't want to leave the pitch.
"Tevez is very important for the team but I took the decision and I think it was the right decision."
The City boss and his feisty Argentine striker were conspicuous by their absence at the team's Christmas party after the game.
City stars dressed in lurid polka-dot outfits and followed a dinner out with a trip to the fashionable Suburbia nightclub in Hale.