The England captain suffered an ankle injury in Mourinho's last game in charge at Everton and has not trained since, so interim head coach Ryan Mason is set to be without him.
Matt Doherty (muscle) is back in contention but Ben Davies (ankle) is still out.
Southampton can welcome back on-loan Liverpool winger Takumi Minamino, who was cup-tied for Sunday's FA Cup semi-final defeat by Leicester.
Striker Michael Obafemi has returned to training following the muscle injury which has ruled him out since January, but he is short of match fitness.
Oriol Romeu (ankle) and William Smallbone (knee) remain long-term absentees.
Tottenham provisional squad: Lloris, Hart, Aurier, Doherty, Tanganga, Dier, Alderweireld, Rodon, Sanchez, Reguilon, Hojbjerg, Winks, Sissoko, Ndombele, Alli, Lamela, Moura, Kane, Vinicius, Bale, Son.
Southampton provisional squad: Forster, Walker-Peters, Bertrand, Vestergaard, Bednarek, Ward-Prowse, Redmond, Armstrong, Diallo, Ings, Walcott, McCarthy, Stephens, Salisu, Djenepo, Minamino, Jankewitz, Adams, Tella, Ferry.
Empoli 
Udinese 
CSKA Moscow 
Rubin 
Slovan Bratislava 
AC Milan 
Sparta Praha 
Atletico Madrid 
Valencia 
Barcelona 
Stade Brestois 29 
Bayer Leverkusen 
Red Bull Salzburg 
Bayern Munich 
Paris Saint Germain 
Inter 
RB Leipzig 
Manchester City 
Feyenoord 
Sporting CP 
Arsenal 
FC Rostov 
Spartak Moscow 
Aston Villa 
Juventus 
Celtic 
Club Brugge 
Dinamo Zagreb 
Borussia Dortmund 
Liverpool 
Real Madrid 
Monaco 
Benfica 
PSV 
Shakhtar Donetsk 
Lokomotiv Moscow 
Dinamo Moscow 
Anderlecht 
FC Porto 
AZ Alkmaar 
Galatasaray 
Dynamo Kyiv 
Viktoria Plzen 
Lazio 
Ludogorets 
Qarabag 
Lyon 
FC Heidenheim 
Chelsea 
FC Midtjylland 
Eintracht Frankfurt 
Manchester Utd 
Bodo/Glimt 
Nice 
Rangers 
Real Sociedad 
Ajax 
Tottenham 
Roma