Tevez is poised to make his first appearance for the club for six months on Wednesday, with Mancini expected to name him on the bench for the Premier League visit of Chelsea. The Argentinian has not played for City since falling into dispute with the club following the infamous Champions League defeat at Bayern Munich.
After an unauthorised three-month absence in Argentina, the 28-year-old returned to training five weeks ago and apologised for his conduct, clearing the way for a return.
Tevez was inspirational as City won the FA Cup last season but Mancini believes his efforts are even eclipsing those of 12 months ago.
"What happened with Carlo six months ago is in the past," Mancini said. "Carlo is part of our plans for the last two months, he is a City player. I think Carlo in this moment wants to play football. He needs to play football, for him and for his future. He wants to play.
"I can see in training he is perfect, better than last year. He wants to play and deserves to play and help the team. I have always thought Carlo is a top player, even when we had the problem."
City trail rivals Manchester United by four points at the top of the table but are looking to cut the deficit by winning their game in hand against Chelsea. Mancini expects Tevez to be ready to start next month as the title race heats up.
"He is getting better but I don't think Carlo can have more than 25-30 minutes," said Mancini. "A player like Carlo needs to play but for 90 minutes, at this moment, it is impossible.
"If he can play 30 minutes, after that 45 in three or four games, then he could have 90 minutes, easily."
Mancini, though, says City may have a "big problem" ahead of the Chelsea game with first-choice centre-backs Vincent Kompany and Joleon Lescott injured. Lescott is ruled out with a groin problem while captain Kompany is unlikely to return from a calf injury.