Mkhitaryan, a £30million off-season signing for United from Borussia Dortmund, has played just 29 Premier League minutes off the bench to begin the campaign.
Wayne Rooney, Juan Mata and Anthony Martial have been preferred ahead of the Armenia star, and Mourinho said the trio's form was keeping Mkhitaryan out.
"The others are playing really well," he said.
"When some managers buy players they play because they think about protecting themselves. I choose this player, I bought this player, I have to show the world I was right.
"No, the first thing I think about is my team. Miki is a super player and so I am sure he will succeed. I am not in a rush to play him to show the world how good he is.
"Maybe he will play at Hull [on Saturday]. We have a very good squad and every weekend we are going to be here and you are going to ask about A, B or C because it's a normal thing."
Mourinho believes discussion over his selection will be common this season, with United having won their opening two games of the league campaign.
The Portuguese tactician also said his decisions led to constant speculation over players' futures.
"It's difficult but if Mata is on the bench, you tell me I want to kick him out and want to sell him," Mourinho said.
"If I don't play Martial it's because he is in crisis, or if I don't play Ashley Young, it's because I don't like Ashley Young.
"If it's Memphis Depay, it is because he is on his way out."