With Phil Jones and Eric Bailly suspended, Lindelof and Chris Smalling are set to start at the heart of United's defence against the Swiss champions.
But Mourinho believes the 23-year-old is better suited to European competition after regular appearances during his four years in Lisbon.
"There is no need for him to adapt to the Champions League but he needs a bit of time to adapt to the Premier league, especially the new Premier League," Mourinho told a news conference.
"He is very bright and very clam and step by step he will be there. I am more than confident for tomorrow [Tuesday], he is a very good player with a very good potential.
"Even if Bailly and Jones were not suspended, probably I would still play Lindelof and Smalling. They are at the same level, they are just different players."
David de Gea, whom Mourinho confirmed will start the match despite his decision to rotate goalkeepers in the Europa League last season, does not see any problem with playing behind a new defensive partnership.
"I feel really well with all my defenders," he said. "They are all great defenders."
Marouane Fellaini remains a doubt for the match as he has yet to recover from a calf problem picked up while on international duty with Belgium.
The midfielder did not train on Monday but Mourinho hopes he will be available, insisting he is a crucial part of his plans.
"He had a [calf] problem with his national team and then he played a match against Greece, and after the match he felt the problem. If his condition improves he will be selected, because I need him," he said.
"He's a very important player for me, much more important than you can imagine."