Fellaini joined the list of absentees, which includes Paul Pogba, after sustaining an ankle injury in Saturday’s win over Southampton following a tackle from Shane Long.
Having watched replays Mourinho, who believes his side have to remain “humble” if they are to extend their unbeaten record this season, was unhappy with the Tipperary man’s challenge but refused to criticise referee Craig Pawson, who booked the Saints striker for the challenge.
“We don’t have Fellaini, we don’t have Pogba, we don’t have Carrick,” said the United boss ahead of the Champions League match against CSKA Moscow.
“All three midfield players we lose for this match so the solutions are not many but we try not to focus on individual battles in specific areas on the pitch.
“Fellaini was lucky, it could be a much worse situation but in a moment when we don’t have Pogba and Carrick, Marouane becomes even more important than he is and not to be here tomorrow is a difficult situation for us. But I expect Fellaini not to be out for a long time and after Crystal Palace there is the international break and Belgium, I think, were the first team to qualify so are not under pressure for a special big match so Fellaini will be back for us.
“For me Crag Pawson is one of the big talents of refereeing and he had an amazing game, in my opinion, he was so calm and in control. No camera for Craig and he made that decision.”
After defeat in the European Super Cup against Real Madrid in August, United are unbeaten in eight matches, winning seven of them.
They had to grind out a 1-0 win on the south coast last weekend and Mourinho told his players they have to be patient and learn to deal with the opposition having spells of dominance.
“We cannot guarantee this line of success but the way to try to keep it is to do what we are doing,” he said.
“If the opponent has moments of superiority we have to be humble like we were against Southampton and cope with the difficult moments of the game.
“In the second half we had to be humble and accept the opponent was on an high and we had to fight hard.
“It was a mixture of our quality and dominating like do but accepting when the opponent has a strong moment you have to cope with it.”
CSKA Moscow, whom Mourinho has previously faced as manager of Real Madrid, Inter Milan, and Chelsea, beat Benfica last time out so they and United are leading the race in Group A.
Victory would give his side a handy three-point cushion ahead of next month’s trip to Portugal, but midfielder Henrikh Mkhitaryan knows they have to be professional in Russia with the criticism from Mourinho after the Basel win still fresh in the memory.
The United boss claimed his side were more interested in playing “PlayStation football” than finishing off their Swiss visitors in the second half.
“Of course everyone knows that Jose Mourinho is very demanding and what he said was right,” said Mkhitaryan.
“He didn’t exactly say names but everyone thinks they have done something bad or made a mistake.
“We are trying to improve that aspect and stay more focused during the whole game and not be doing fantasy football or PlayStation, as he said, in the last 25 minutes.”