Paris Saint-Germain and former Spurs boss Mauricio Pochettino are said to be confident of signing Alli, who has been cast aside by Mourinho this season, on loan until the end of the campaign.
Tottenham chairman Daniel Levy is understood to be concerned about the possiblity of replacing a player of Alli's ability in what has been a difficult market this month, while there are also fears over a lack of depth should there be a coronavirus outbreak at the club.
"I expect [him to still be here],” Mourinho said on Wednesday. “I'm saying that since the beginning of the transfer window. I was not expecting anyone to leave, I was not expecting anyone to come.
“Until no, January 27, we're almost in the end. I don't believe anything is going to happen but it's open still.”
Pressed on whether there was any possibility of Dele leaving before the window closes on Monday, the Portuguese added: “Football is football, the transfer window is open. Sometimes unexpected things can happen but I don't expect it.”
Alli was not involved in Spurs’ FA Cup win over Wycombe on Monday night because of a “small tendon problem” and Mourinho confirmed that the midfielder would not be back for Thursday’s clash with Premier League champions Liverpool.