Ibrahimovic is expected to be out for a month with a knee injury, while manager Jose Mourinho has revealed that top scorer Lukaku is doubtful after a clash of heads against Southampton.
"I don't know," Mourinho told Man Utd's official website, when asked of a possible Lukaku return.
"I know that normally bad, bad news arrives immediately. Bad news didn't arrive. I think that there's a problem for the next two matches, for sure."