United travel to Bournemouth on Wednesday and have a trip to Wembley Stadium three days later, but Mourinho said anyone who impresses at the Vitality Stadium could win a spot against Spurs, per the Mirror's David McDonnell:
"Rotating is not the right word. If I play a player against Bournemouth and the player is phenomenal, he plays the semi-final.
"So it's not rotating, because rotating looks like a player that plays against Bournemouth is to give a rest to somebody that is going to play against Spurs in the semi-final.
"So the word is not rotation, it's an opportunity for people to play and to try to get a place in the team for Spurs and if some of the guys that played against West Brom don't have a place in that team, they don't have a place in that team."
The Red Devils lost 1-0 at home to West Bromwich Albion on Sunday to assure rivals Manchester City of the Premier League title, and the FA Cup is United's last remaining chance at silverware this season.
Mourinho's side have spent hundreds of millions on new players since his arrival—£89 million Paul Pogba and £75 million Romelu Lukaku among them—but neither could prevent a sorry home defeat to the Baggies.
Bill Rice of BBC Radio Manchester provided further quotes from the United chief, who appeared to indicate there are some among his squad prioritising the wrong things:
He added: "I met players at 30, not consistent at all, and I found boys of 18, 19 and 20, real men, real pros, so it's not about the age."
One example of the kind of player Mourinho is alluding to is Scott McTominay, 21, who has grasped his chances in central midfield over the latter half of this season and is now frequently in the United first-team squad.
Tottenham have played their home fixtures this season at Wembley and will almost treat Saturday's clash as a home fixture, although they first have a trip to Brighton & Hove Albion on Tuesday.
Mourinho will hope a visit to the Vitality Stadium will provide certain players with the boost in confidence needed ahead of Saturday's semi, although broadcaster Pilip De Bruin argued it's not the players' fault at all:
The defeat to West Brom was an especially hard pill to swallow considering it gave City the title, and even more so when considering United beat their biggest rivals 3-2 at the Etihad Stadium a week earlier.
Beating the Citizens to the FA Cup would be one way to help seal some redemption after that, and Mourinho is clearly open to changing his first-team plans ahead of the semi-final duel.