Since being substituted at half time against Everton on the opening day, the 24-year-old has played just 21 minutes in the Premier League - as a substitute against Manchester United in October.
Daniel Levy had reportedly rejected an approach from French side Paris Saint-Germain to take Alli on loan in the summer and Mourinho confirmed once again that it is up to the board to decide who stays and who goes.
"One thing is me understanding the players, another thing is the players' situation. I don't make decisions about selling A, B or C, or letting D, E or F go on loan," Mourinho told the Daily Telegraph.
"I am responsible for the players that belong to my squad and are working with me. The ones that are not playing enough time in their minds, in their ambitions, they have only one thing to do, which is to use the time they play to show me they are better than the ones having more minutes. There is no secret to that.
"I don't have any problems with Dele. I don't have any problems with anyone. I'm really happy I don't have personal issues with any of my players. Players are happier when they play. They're not happy when they don't play and I don't blame them. That's just the way it is. The concept that wins above everything is the concept that the team is more important than any one of us."