Wayne Rooney will miss Manchester United's home clash with Middlesbrough on Saturday as he continues to be sidelined with injury.
The United skipper missed the Red Devils' Boxing Day victory over Sunderland in the Premier League after picking up a knock in training.
Mourinho stated after that win that Rooney's return against Boro was unlikely, and the United manager confirmed at a pre-match news conference that the England international remains absent.
"Out," he replied when asked about Rooney's fitness, before adding "not really" when pushed for a return date for the 31-year-old.
Mourinho is unlikely to rotate his squad this weekend despite the quick turnaround after Monday's win at Old Trafford, with the Portuguese keen to stay at full strength as they look to maintain a five-game winning run in all competitions.
"No [I will not rotate]," he said. "Middlesbrough is the next game and the next game you play to win.
"So against Middlesbrough we are going to think about Middlesbrough and try to choose a team that gives us guarantees and chances to win the match.
"That includes everyone that is available and everyone we think is important for the match. We are going to play with the players we think are the best to play."
United's return to form has put them back in touch with the top four and Mourinho is not surprised by his side's upturn in fortunes.
He added: "The momentum of playing well comes from a long time ago. It's difficult for me to remember the last match where we didn't play well.
"But the reality is that in the last four Premier League matches and five competitive matches we've managed to win and in this moment we need points, so let's try to get three more at home at Old Trafford for our fans.
"It is a good day to play football, the last day of the year, so let's try."
