The Portuguese has reportedly been informed that he must balance the books during the January transfer window if he is to bring in a marquee signing.
One player said to be close to the Old Trafford exit is Armenian playmaker Henrikh Mkhitaryan, who has fallen out of favour following a bright start to the campaign and now struggles to even make the squad.
Asked if Mkhitaryan, or any of his other fringe players, are up for sale, Mourinho told reporters: "My approach to players is that every player has a price. It doesn't matter who he is. It doesn't matter the level. It doesn't matter the prestige, the status. I think every player has a price.
"And I am not the kind of blind manager...blind in the sense of, this player is untouchable, can never be sold. I think every player has a price. So when the transfer window is open, it's also open for any club that is interested in our players. Then it's up to us to make the decision: yes or no.
"It's up to us to decide what we think is the right price. But Mkhitaryan played the last match in the FA Cup and probably will play the next one [against Stoke].
"He's a little bit the same in relation to other players that are involved in this gossip of the transfer market. He is our player and a very good player. So Saturday [he is] training, then Sunday [he is] selected and Monday [he will] play."