"A disaster. Obviously a disaster but that's football," Mourinho told British media when asked how damaging it would be to lose Ibrahimovic to injury.
"It's not a surprise (how many goals he has scored). In Spain, Messi and Cristiano (Ronaldo) have a lot of penalties to score. They are phenomenal players with lots of penalties to score goals.
"Here, Zlatan has 18 (league) matches and one penalty. It's not so easy to score goals."
Depay has played just 20 minutes of Premier League football this season and Mourinho said he would not stand in the way of the Dutch winger leaving the club amid reported interest from Everton and Italian side Roma.
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"I have to say that in the past couple of months my decisions in relation to Memphis were influenced by the feelings and information that he would like to leave in January," Mourinho added.
"And that we were going to have a real offer that we would be willing to accept. That obviously influences me."
(Reporting by Shravanth Vijayakumar in Bengaluru; editing by Amlan Chakraborty)
