After a fabulous first half of the current campaign, City's talisman Tevez has seen his season almost grind to a halt in recent weeks - the Argentine has only found the back of the net once in his last nine appearances.
The 27-year-old plundered 20 in 26 matches prior to his lean spell but 11 club matches since February 2 appear to have taken their toll on Tevez.
There will be no respite in the immediate future, however, as City look to overturn a 2-0 first-leg deficit against Dynamo Kiev tonight in order to progress to the Europa League quarter-finals. And their Premier League exertions continue at the weekend, with a tough away trip to Stamford Bridge on Sunday.
Argentina have decided to omit Tevez from their squad to face USA and Costa Rica later this month, and Mancini is hoping the break will give his star striker a chance to recharge his batteries.
"Carlos needs to work in the next week," he said. "In the last 45 days, it's been impossible. If we have 20 or 23 players when we play four or five games in two weeks, we would be able to change six players every game. We don't have that option and when you can't train it's difficult to keep the same level for one month or 45 days. That's the same for all the players.
"It isn't only Carlos who has lost his sharpness, all the players have. But if we don't have problems against Kiev or Chelsea, then we can recover all our players after the internationals. Then they can come back very well, like they were four or five weeks ago. But the next two games will be very hard."
With City still firing on three fronts - the Eastlands outfit have an FA Cup semi-final tie with rivals Manchester United in April - Mancini is worried how his side will cope with the strain.
He said: "If we get into the quarters, we will play every three days until the end of the season. That will be a big issue because when you become a top club, you should have 25 players available for each game. If not, it is a big problem.
"But I always want to win and that should always be our mentality."