Tevez is poised to make his first appearance for the club for exactly six months with Mancini expected to name him on the bench for the Barclays 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.
But after an unauthorised three-month absence, the 28-year-old returned to training five weeks ago and apologised for his conduct, clearing the way for a return.
The club's top scorer for the past two seasons could now give City a lift at a vital time in the title race and Mancini has sensed his determination.
Tevez was inspirational as City won the FA Cup last season but Mancini believes his efforts are even eclipsing those of 12 months ago.
Mancini said: "What happened with Carlo six months ago is in the past. 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 is not expecting Tevez, who spent most of the winter in Argentina without permission, to be ready to start until next month.
But after two run-outs for the reserves, the Italian believes the time is now right to bring him back into the first-team fold.
He said: "He is getting better but I don't think Carlo can have more than 25-30 minutes.
"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."
City still have defensive problems ahead of the 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.