A bit of pep, a dash of zing, to perk up their title challenge at a time when it is in danger of stalling.
City stand on the brink of their first league championship since 1968 - Tevez can push them over the edge.
This argument points to City's recent struggles in front of goal - Sergio Aguero, Edin Dzeko and Mario Balotelli having a lean time of it compared with their prolific early-season form.
No doubt, a happy Tevez is a brilliant footballer.
Yet the contention that City need another big-name forward is like saying the Big Fat Gypsy Weddings 'pineapple dress' just needs an extra splash of colour, and maybe a few sequins.
City's squad is overblown with world class players - they have their problems but a lack of talent is not one.
Aguero and David Silva are City's kingpins - the only two attacking players guaranteed a start in the big games.
Dzeko has been in and out of the side, clearly frustrated but still willing to put in a wholehearted shift.
Balotelli's temper, meanwhile, has led to the odd self-imposed exile. But when not suspended he has played several positions (including wide right) without complaint.
You very rarely get the best out of a player in such situations - so given the circumstances, they have actually been very impressive.
If Mancini can find a role for Tevez to support Aguero and Silva, all well and good.
But the Argentine's career at both Manchester clubs has followed the same trajectory. Happy when in form and playing every week; quick to whinge when pushed into a marginal role, incapable or unwilling to understand that he is on the bench because others offer a greater chance of victory.
Put simply, Tevez only sparkles when he is the centre of attention.
There is a reason why he has been compared to Rodney Marsh, the man whose arrival at Maine Road scuppered City's last serious title challenge.
Unless Mancini is prepared to hand Tevez the reins of City's title challenge (and if he is, he is mad), the player's prospective role is as a slight trade up from Dzeko and Balotelli.
But exactly what evidence exists to suggest that Tevez would relish such a role? None that I am aware of.
Tevez was out of sight and out of mind. City didn't have to pay him, they didn't have to watch him train half-heartedly, or skulk out of the club's Carrington training complex with his entourage. Plus they were able to look tough and make a stand.
Now he is back, I don't see the benefit. City have the players to win the league, and the suggestion they need an extra boost is unfounded.
They have the best squad by a long way, and they are already top. A limited Manchester United side have punched almost ludicrously above their weight to stay in touch, but this season it looks like the Reds who are the plucky challengers, set to fall away late on.
Apart from the Europa League - clearly a secondary priority - City have nothing to distract them from the final 13 league games of the season.
Nor do City have to worry about the psychological barrier of closing out the Premier League for the first time, which United wrestled with 20 years ago.
They have a squad packed with players who have won virtually every trophy going - World Cup, European Championship, Champions League, Europa League and every major domestic title - there is at least one player in the dressing room at Eastlands who knows what it takes to win all of the above.
City are on track. For all Tevez's ability, he merely risks derailing City.
If he were willing to assume the Michael Owen role, play a few easy games and help keep the more important legs fresh, fine.
For all Owen's tedious self-regard, he is happy to wait his turn, and usually scores when he does play.
That is Owen. It is emphatically not Tevez.
City do not need his talent, and they certainly do not need his dressing room 'influence'.
Send him back to the golf course.