Victor Wanyama has not started a game since defeat to Burnley earlier this month, having struggled to shake off a back problem.
But the Kenya international has been named in midfield alongside Mousa Dembele, with Mauricio Pochettino appearing to opt for a 4-2-3-1 formation.
Harry Kane leads the line ahead of Christian Eriksen and Dele Alli.
Spurs have lost six FA Cup semi-finals in a row and are aiming to avoid a record seventh straight defeat.
Pochettino has cast his side as underdogs but they have an opportunity to come of age by booking their place in the final at the expense of their capital rivals.
Tottenham XI: Lloris (C), Trippier, Dier, Alderweireld, Vertonghen, Wanyama, Dembele, Son, Eriksen, Dele, Kane.
Tottenham subs: Lopez, Davies, Walker, Wimmer, Sissoko, Nkoudou, Janssen.
Chelsea XI: Azpilicueta (c), David Luiz, Ake; Moses, Kante, Matic, Alonso; Willian, Batshuayi, Pedro.
Chelsea subs: Begovic, Zouma, Terry, Chalobah, Fabregas, Hazard and Diego Costa.
What they're saying
Mauricio Pochettino: "If there is one favourite it's Chelsea because they are top of the table, because of the experienced players and the manager that they have.
"But we are in a good moment, too, and we are hungry to challenge this type of team."
Antonio Conte: "Tottenham now is a really great power in English football.
"There is a moment you have to finish considering yourself an underdog. I think this is the right moment."