City have been dealt a big blow ahead of Saturday's game against Arsenal with the news that Carlos Tevez will miss out to a knee injury picked up on international duty.
Mark Hughes has also admitted that there are fitness worries over Robinho, who lined up against Tevez in Brazil's 3-1 win over Argentina last weekend.
"We heard yesterday (Monday) that Carlos had a knee problem, our doctor has spoken to the Argentine medical people and the feeling is that he is out for the weekend so he will not play against Arsenal,” confirmed the boss.
"The hope is that he will be OK for the derby, but we will have to determine that when he comes back. He is staying with the national squad because he needs acute treatment at the early stage of the injury, which is what he can get now. Flying him back quickly might compromise the injury, so he will be back towards the end of the week so we can assess him and hopefully get him ready for the United game."
International fixture windows are a time when club managers, like Hughes, cross their fingers once their players are away with big league games on the horizon, but City's chief is philosophical over the news of his Argentinean striker.
He added: "It was an impact injury, he has twisted his knee but it could have happened in a training session or just walking down the road. Its part and parcel of the game, we feel it's not going to compromise him too much and that it will only be one game that he has to miss."
There is more hope that Robinho may be available for the sold out, mouth-watering visit of the Gunners on Saturday.
It's a different situation with Robi. It's an old injury that he aggravated last year, just above his ankle. We are going to get him back as soon as possible, the hope is that he will be an option for the weekend but we need to get him back, which we will do today.
Several of the Blues' squad will be in action in midweek, but Hughes also pointed out that some will not and therefore have extra time to prepare for the resumption of Barclays Premier League duties this weekend.
"Shay (Given) is having a bit of family time and not playing for the Republic tonight, Kolo and Ade played at the weekend but only had the one game so will be back on Wednesday. We are getting some of the internationals back quite readily, but some are still away, for example Craig Bellamy's one game is on Wednesday,” he said.
"It's the same as it is in any international week, you wait by the phone and hope everybody comes through unscathed. We have been affected by this international window, so I hope we don't get any more injuries.”