Watford expect Samir to be fit for Roy Hodgson’s reunion with former club Crystal Palace at Vicarage Road.
Samir was forced off in the closing stages of Saturday’s 1-0 win at Aston Villa with a head injury, but boss Hodgson said there were no concussion issues and the Brazilian centre-back trained on Monday.
Conor Gallagher will return to the Palace squad for the trip.
The on-loan Chelsea midfielder was ineligible to play against parent club Chelsea on Saturday, but is available once again.
Keeper Vicente Guaita, who was substituted at half-time at the weekend, is expected to be fit, but full-back Joel Ward – who sat out against the Blues with a knock – will be missing once again, as will fellow defender Nathan Ferguson (thigh).
Watford provisional squad: Foster, Femenia, Cathcart, Samir, Kamara, Louza, Sissoko, Kayembe, Cleverley, King, Dennis, Sarr, Bachmann, Ngakia, Troost-Ekong, Kucka, Joao Pedro, Masina, Sema, Kabasele, Kalu, Hernandez.
Crystal Palace provisional squad: Guaita, Andersen, Guehi, Mitchell, Hughes, Kouyate, Schlupp, Olise, Edouard, Zaha, Butland, Clyne, Tomkins, Riedewald, Milivojevic, Eze, Mateta, Ayew, Benteke, Matthews, Adaramola, Kelly, Rak-Sakyi.
