Mourinho insists that the squad is "the same" as last season, though, as Grant will be used in reserve, while Dalot is also effectively being used as cover and Fred takes over from retired midfielder Michael Carrick.
Speaking to Sky Sports News ahead of United's Premier League opener against Leicester City, Mourinho said: "It is the same, the same squad as last season. We changed the goalkeepers with Lee because Joel [Pereira] is such a good young goalkeeper that he needs to play.
"We changed Daley Blind for a 19-year-old kid (Dalot) that we believe has the potential to play right-back or left-back and we changed Michael Carrick for Fred so our squad is the same. [Fred] is a midfield player, he's not a striker, not a central defender, he's a midfield player that technically is very good.
"In that sense, typically, the Brazilian player has a very rich luggage in technical terms and also in some static beauty movements of football. He's a player to really enjoy, if he adapts as soon as possible.
"For us, it was a very simple market as you can see. The only thing we can do is to work. There are ways to improve your team: one way is to spend a lot of money and to bring in lots of important players, another way is to work and that's the way we have to do it. I relish every challenge, it doesn't matter what, I love to work. That's the only thing I can promise, work hard. I am always confident, that's management."
Fred has been named in United's starting lineup for this evening's clash against Leicester.