Speculation is rampant he could join Mauricio Pochettino's Paris-Saint Germain side on loan for the rest of the campaign.
“In every dressing room are unhappy players," Mourinho said. “For sure. If any one of us, of my tribe, tells you that in his dressing room are only happy players, I don't think it's true. Or somebody is so so lucky to have a miracle in his hands.
“Then you can have [an] unhappy professional and the unhappy professional is the one that is unhappy but feels that his duty is to work, work, work and work.
"And there is the unhappy player that believes that it's not his job to fight and to work every minute for the squad and for the club."
Mourinho did make it clear that he would have have a replacement lined up for Alli this month if he was to let him join another club.
“The question is if I let Dele go without getting a player in exchange and I'm not going to answer that," Mourinho said.
“It's not a question that I am comfortable to answer. Of course, I would know how to answer.
"But I am not ready to answer. I am not ready to make public my vision of the situation."