Tevez has not played for City since September, but having reconciled his differences with the club hierarchy is expected to be on the bench for City's crunch clash against Chelsea on Wednesday.
And with the Argentina international set to return to the City side for the first time in six months, Hart believes it will be like having a new signing on the pitch.
"I haven't actually trained with him," Hart said in the Sun. "But those who have assure me he's doing really well. It's down to the manager to assess it. But a fully fit and firing Carlos has got to be a positive for us.
"We've got energy in the team and we've got a lot of firepower. But Carlos brings us more of that. The strikers who are here now have got us in a position where we could get a record points tally in the league. But having Carlos back will be like a new signing."
Defeat to Swansea nine days ago saw City surrender their lead at the top of the Premier League for the first time since October, but Hart believes his side are capable of gunning down leaders Manchester United.
"It doesn't feel good," Hart said. "As soon as the whistle went at Swansea, we knew. We didn't need to check the results, we knew what would have gone on elsewhere.
"We were hurt and we'll show how hurt we are with our performance on Wednesday against Chelsea. Now we have to push on, we have a big game against Chelsea. We need to focus on what we're doing and we should be OK.
"One result can literally change everything. It's madness but it's great. Being four points behind won't have any bearing on how we play.
"I've never won [the league] so it's hard to know what a title-winning side feels like. But we've got a good spirit, good attitude.
"And I'm sure anyone who has won a title will tell you that's what is required. We have all the ingredients. All we're short of is the medal round our necks."