With the Frenchman unavailable for domestic duty until at least the Carabao Cup quarter-final meeting with Championship promotion hopefuls Bristol City on 20 December, Mourinho plans to involve him tomorrow as his side look to seal their place in the last 16 of European football's elite club competition.
"Zlatan is not injured", the boss told a press conference. He needs sometimes very hard work on the area that supports the knee that had the problem. When that hard work comes, so does fatigue.
"He is very happy to play tomorrow".
Mourinho has confirmed that Luke Shaw will get a rare call-up to the squad on Tuesday night but he refused to divulge whether the left-back will start or be named on the bench. We didn't finish first in the group yet.
"I'd have to think", said Mourinho. I'm going to make a few but not too many changes, ' said Mourinho when asked about Shaw.
"He's [Shaw] working to have an opportunity and sooner or later, the opportunity will arrive".
'We didn't qualify yet and I need to keep a certain balance in the team. Selected for tomorrow, yes, for sure. It is the next match so it is the match that matters.
Last season he was used far less than under Louis van Gaal, and at the start of the current season he had to make do with making appearances off the bench.
Luke Shaw could appear for just the third time this season, Sergio Romero replaces David De Gea in goal and the injury list contains Nemanja Matic, Michael Carrick, Marouane Fellaini, Phil Jones and Eric Bailly. "Since he was back from injury he's been phenomenal".