Both Javi Gracia and Maurizio Sarri name unchanged teams from their last matches.
Watford name the exact 11 and same seven substitutes from their 2-0 win at West Ham on Saturday.
Watford XI: Foster, Femenia, Cathcart, Kabasele, Holebas, Capoue, Doucoure, Sema, Pereyra, Deeney, Deulofeu.
Substitutes: Gomes, Mariappa, Cleverley, Success, Masina, Quina, Okaka.
For Chelsea, Ruben Loftus-Cheek, who came off the bench against Leicester on Saturday, is not included in the 18-man matchday squad, with 18-year-old Callum Hudson-Odoi among the substitutes.
Chelsea XI: Arrizabalaga, Azpilicueta, Rudiger, Luiz, Alonso, Kante, Jorginho, Kovacic, Willian, Hazard, Pedro.
Substitutes: Fabregas, Barkley, Caballero, Giroud, Hudson-Odoi, Cahill, Emerson Palmieri.