Watford forward Isaac Success returns to the squad for the Premier League clash with Chelsea.
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.
Chelsea remain without defender Antonio Rudiger and midfielders N’Golo Kante and Ross Barkley because of injury.
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.
Defender Andreas Christensen is close to returning from a hamstring problem but unlikely to be involved at Vicarage Road, while Ruben Loftus-Cheek (Achilles) is a long-term absentee.
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.
'Obviously Messi is the best player in history and being compared to him means that you're doing things right, but I try to be myself': Barcelona star responds to comparisons with Argentine legend
'Darwin Nunez would be gold for Arsenal': Liverpool legend claims Gunners should have signed Uruguayan striker in January
