Pogba pulled out of Saturday's FA Cup clash with Huddersfield Town due to illness on the morning of the game, with his withdrawal coming amid rumours of a breakdown in the relationship between him and Mourinho.
However, the France international was soon back in training, and Mourinho suggested that he could return in time for the trip to the Estadio Ramon Sanchez Pizjuan.
"I don't think it's fair to speak about the responsibilities of a player. I don't even like the fact that the player that cost X millions doesn't have the same responsibility as the player that cost three times X," Mourinho told reporters at his pre-match press conference.
"The responsibility is for everyone so I don't like that approach. I understand for you but not for me. The same way when I decide a team to play, I don't look to the age, the salary, the transfer fee, because that's not also fair.
"I opened the training session today and I opened in a period where we normally don't open. We normally do it in the warming-up and in the first simple drills of the training session, and this time we did it for quite a long time, and in the last period so you could see the players in a competitive situation.
"When a player is in that situation it's because the players are normally ready and without problems, so you could see that in training some people that didn't play against Huddersfield with problems, like Pogba, [Antonio] Valencia, [Marcus] Rashford and [Ander] Herrera, so I think in an objective way you could look at it."
Pogba has been subbed in two of his last three games for United, and was dropped to the bench from the start for the other.