Paris St Germain, now managed by former Spurs boss Mauricio Pochettino, are pushing to sign the 24-year-old on loan for the rest of the season.
Alli has fallen out of favour under Mourinho, who has barely used him this season, but chairman Daniel Levy is understood to be hesitant to let him leave.
And Mourinho is not expecting any movement ahead of Monday's deadline.
"I expect (him to be here) and I am saying that since the beginning of the window," Mourinho said ahead of his side's Premier League clash with Liverpool on Thursday.
"I was not expecting anyone to leave or expecting anyone to come. We are almost at the end of the window. I don't believe that anything will happen, but it is open still.
"Football is football and the transfer window is open and sometimes unexpected things can happen, but I don't expect it."
If any deal is to happen it would be late in the window, something Tottenham traditionally specialise in, and that goes for any potential arrivals too.
Mourinho has said all month that he does not believe the club will make any signings and he is sticking to the message.
"Don't think so. Honestly, I don't think so," he said. "As I was saying before, the transfer window is open and anything can happen until the last second.
"I'm convinced nothing is going to happen. If something happened it would be a huge surprise for me."
Alli will be missing from Thursday's game with Liverpool as he is injured and Mourinho hinted that several of his other players will also miss the game, though chose not to reveal who.
Full-backs Matt Doherty and Ben Davies are doubts, while Giovani Lo Celso is a long-term injury problem.
"We have more problems than that what I'm not going to share," Mourinho said. "You have to wait for tomorrow, but we have a little bit of more problems than that."
Liverpool won the reverse fixture in December with an stoppage-time goal to go three points clear at the top of the Premier League but their form has fallen off a cliff since.
They are winless in their last five and are now seven points shy of leaders Manchester City.
Mourinho says that every top club will have a dip this season and thinks they will bounce back.
"Every club, especially the traditional top six, has this situation," he said.
"Not one team started with winning and is still winning after 19 matches and a few months of competition. Everyone has a difficult period. Some early, some later, some in the middle.
"Great evolution in what is historically considered below top-level team and ambitions, great performances from many of them. Very good teams, very good squads.
"I feel completely natural that some results happen. And then Liverpool had a period where the results are not going in their direction. But the coach is the same, the players are the same and the team is the same."