England midfielder Frank Lampard serves a one-match ban, while they are also hoping that Czech Republic midfielder Jiri Jarosik - the most expensive player in the history of Russian football - will complete his loan move from Spartak Moscow in time to play.
The meticulous Mourinho has had scouts watching United, and will give them plenty of respect.
He said: "We have watched them like we watch any other team.
"We may change a few players for the game, if we can find any to change, but we will play to win the FA Cup. We will play to win the Carling Cup.
"Winning the Premiership or the Champions League is more important but we will not turn any trophy down."