The Spaniard has endured a stop-start campaign due to a thigh injury sustained at the end of last season but featured in the win at Norwich last time out and, although he was forced off with a niggle, he has returned to training and is in contention.
Goalkeeper Daniel Bachmann is not expected to feature due to a knee injury and, while Joao Pedro has recovered from a similar issue, this game is set to come too soon for him.
Defender Lascelles damaged a thigh muscle in last Friday night's 1-1 draw with Leeds, while summer signing Willock suffered a freak toe injury in training, and both men are likely to be sidelined until after the forthcoming international break.
Watford provisional squad: Foster, Elliot, Femenia, Ngakia, Troost-Ekong, Cathcart, Kabasele, Sierralta, Masina, Rose, Etebo, Gosling, Louza, Cleverley, Kucka, Tufan, Sissoko, Sema, Sarr, King, Fletcher, Dennis, Hernandez.
Newcastle provisional squad: Darlow, Gillespie, Manquillo, Krafth, Lewis, Clark, Fernandez, Schar, Hayden, Ritchie, S. Longstaff, Hendrick, Murphy, Fraser, Saint-Maximin, Almiron, Joelinton, Gayle.