Watford will be without suspended midfielder Roberto Pereyra, although the Football Association have reduced his ban from three matches to one.
Miguel Britos and Valon Behrami both return from suspensions, but Craig Cathcart remains sidelined by injury.
Everton will be without Yannick Bolasie for the first time this season because of a knee injury which could rule him out for the rest of the campaign.
However, Seamus Coleman is fit despite suffering a head injury last weekend.
WHAT THE MANAGERS SAY
Everton manager Ronald Koeman on Romelu Lukaku's form: "You can have a good run of scoring goals and then have a bit of time where you don't really get big chances to score.