Nathaniel Chalobah has been ruled out for an unspecified period with a knee injury.
West Bromwich Albion have failed to score in three of their four Premier League encounters with Watford, but they did win the other 3-1 at The Hawthorns last season.
Watford have won 11 points from their six PL matches of 2017/18 - their second-best tally at this stage of a top-flight season.
The Hornets are aiming to extend their club-record total of three consecutive top-flight away victories to four.
West Brom’s next defeat will be their 200th in the Premier League.
Tony Pulis: "Watford have gone under the radar with the quality of player that they've brought in. They look a very capable team and it'll be a tough game."
Marco Silva: "It's a difficult situation (Chalobah). We need to find a solution, to be strong in our way."
Referee: Michael Oliver
Assistants: Simon Bennett, Mick McDonough
Fourth official: Geoff Eltringham