Pogba missed the FA Cup win at Huddersfield Town due to illness after Mourinho had told reporters the France international would definitely play in the fifth-round clash.
Asked about his absence before United's 2-0 win at the John Smith's Stadium, the United manager said "I don't know and, honestly, I don't care" how long the player would be out.
The midfielder has struggled for form in recent weeks, with Mourinho replacing him during Premier League defeats away to Tottenham and Newcastle United.
Mourinho subsequently hit out at reports claiming his relationship with Pogba had broken down, repeatedly calling the speculation "lies".
After Pogba played a full part in training on Tuesday, Mourinho suggested the club's record signing was ready to come back into the side.
"I opened training today and in a period where we normally don't open - we normally do warming-up and the simple drills," he said. "This time we did it for a long time and in the last period so you could see the players in a competitive situation. When the player is in that competitive situation it is because they are normally ready and without problems.
"You could see in that training some people who didn't play v Huddersfield like Pogba, [Antonio] Valencia, [Marcus] Rashford, [Ander] Herrera. So I think in an objective way you could look at it."
Pogba's recent performances have been criticised, but Mourinho suggested the France star should not be judged harshly simply because he cost United £89.3million.
"I don't think it's fair to speak about the responsibilities of a player," Mourinho said. "I don't like the fact that the player cost X million doesn't have the same responsibility as a player who cost three times X.
"The responsibility is for everyone, I don't like that approach. I understand for you [the media], but not for me. When I decide a team I don't look at age, salary, transfer fee, because I think that's not fair."