The Nigeria international has not played since the end of August with a groin injury, while midfielder Etienne Capoue is not 100 per cent after a month out with a back problem but could be in contention.
Midfielder Domingos Quina is out for a fortnight with a groin problem sustained in the Carabao Cup defeat at Everton, while Troy Deeney (knee), Ismaila Sarr (leg), Danny Welbeck (thigh) and Tom Cleverley (heel) are all still missing but Jose Holebas returns from a one-match suspension.
Centre-back Rudiger will next week see a consultant about a pelvic problem which has kept him sidelined since mid-September, while Kante (groin) and Barkley (ankle) need more time to recover.
Watford provisional squad: Foster, Dawson, Mariappa, Prodl, Kiko, Foulquier, Doucoure, Hughes, Capoue, Deulofeu, Gomes, Janmaat, Cathcart, Kabasele, Chalobah, Pereyra, Gray, Success.
Chelsea provisional squad: Arrizabalaga, Azpilicueta, Zouma, Tomori, Alonso, Jorginho, Kovacic, Mount, Pulisic, Willian, Abraham, Caballero, James, Guehi, Pedro, Hudson-Odoi, Batshuayi, Giroud.