Watford will have midfielder Etienne Capoue available for the Premier League match against Liverpool following suspension.
Defender Sebastian Prodl has also been training again following his leg problem so could be involved.
Venezuela forward Adalberto Penaranda has received his work permit, but is not expected to be thrown straight into action.
Midfielder Tom Cleverley is stepping up his rehabilitation after a combination of hamstring and Achilles trouble, along with defender Daryl Janmaat (knee).
Provisional squad: Foster, Mariappa, Cathcart, Kiko, Holebas, Chalobah, Doucoure, Hughes, Pereyra, Deulofeu, Isaac Success, Gomes, Masina, Wilmot, Kabasele, Deeney, Gray, Okaka, Capoue, Prodl.
Adam Lallana is out but captain Jordan Henderson returns to Liverpool’s squad.
Henderson sustained a recurrence of a recently-healed hamstring injury and left England duty early but has recovered sufficiently to be included in the squad.
Lallana is ruled out after a minor knock in training.
Provisional squad: Alisson, Alexander-Arnold, Gomez, Van Dijk, Robertson, Wijnaldum, Shaqiri, Milner, Salah, Firmino, Mane, Mignolet, Gomez, Matip, Lovren, Moreno, Keita, Fabinho, Henderson, Sturridge.