The France international was shown a straight red for his tackle on Hector Bellerin in the Red Devils' 3-1 win over Arsenal at the Emirates. This has resulted in a three-match domestic suspension and United refused to appeal the red card appeal.
Nemanja Matic picked up a muscular injury in United's 4-2 win over Watford. Despite the pain, the Serbian international started against Arsenal. The former Real Madrid and Chelsea manager has already confirmed the midfielder will start against Pep Guardiola's side.
Mourinho is left with Ander Herrera, Marouane Fellaini, Michael Carrick and Scott McTominay as the other midfield options in the squad. The decision on the Belgium international's involvement will be taken on Saturday, while the ex-Tottenham man has been ruled out for the clash.
Herrera and McTominay are the two fully fit players at his disposal and one of the players, along with Fellaini (if recovered) has a chance to partner Matic in the midfield against City. Mourinho has decided against revealing who will take Pogba's place when Guardiola's men visit Old Trafford for the derby clash.
"I think you all want to know how we are going to play. Everyone connected with football professionally or as a fan there is those questions: 'Who do we play? 'Who is going to play?' 'How are we going to try to play?' I'm not going to tell," Mourinho explained, as quoted by the Manchester Evening News.
"Even the players, they do not know who is going to play. We are working on principles of play. I want every player to be connected with it and ready for it.
"With the problems we have with absences it is important that other players are ready to play or be on the bench and come on and to have different roles than they are used to.
"So the work was much more global than the specificity of the 11 players who are going to start. I don't want us to feel any kind of pressure. I want us to feel it as a match like we are going to have another one or two days later against Bournemouth.
"We want to win, we want to play well, we are going to try and let's see the direction of the game."