The Spaniard received his first start of the season during Man United’s 2-2 draw with Stoke last Saturday and received criticism from supporters for his performance.
And Mourinho, speaking after the game, noted that he opted to hand Michael Carrick a place on the bench instead as part of his rotation plan this month.
“No reasons to be out,” Mourinho said.
“We are playing only with two midfield players, with Matic and Pogba, who are playing really well and without reason to change, the only match we decided to play with three he played, today we went back to two again and I had on the bench Carrick and Fellaini, which were also important players last season.
“We have a group of players who must be ready to play and not to play. Ashley Young was not on the bench in the last match and today he started the match and played 90 minutes and the next match you can have another surprise of some player you think is going to play and is not going to play.
“It’s the squad we have, I have to use the players and that’s the life in clubs with squads of quality.”
The fact that Mourinho can leave last season’s player of the year out of the match-day squad and still have Pogba, Nemanja Matic, Fellaini and Carrick to call upon is a powerful testament to the sheer strength and depth of his squad.
More importantly, however, it nods towards a capacity within this side for a litany of players to step up and produce decisive performances. He will not want to rely on specific individuals to come up with the goods every week – this was often the case last season – and the current diversity and friendly competition in this group is a wonderfully positive sign.