Tevez was told by manager Roberto Mancini that he would never play for the club again after refusing to warm up as a substitute against Bayern Munich in the Champions League, but has since returned to the set-up and scored a hat-trick in their 6-1 win at Norwich on Saturday.
Despite his winter absence, Tevez is contributing nothing but positive vibes according to Hart.
"We have been a bit dry on goals recently, so that fresh Carlos input has been awesome," said Hart. "You can say what you want about Carlos Tevez, but when he plays, he plays to win and he plays for his teammates.
"There are far more important things in our lives than what went on and what didn't go on.
"We have that goal of trying to win the league and Carlos has bought into that. He has not come in and tried to make any big statements. We have just all moved on."
City host United on Sunday with the Sky Blues sitting five points behind their rivals with four games left to play.