Meanwhile, Middlesbrough will be aiming to collect consecutive victories after recording their first win of the season on Tuesday.
Match preview
Watford enter Tuesday's contest in seventh place after collecting nine points from their opening six league games.
Having lost for the first time in the Championship this season at the weekend, Watford are currently winless in their previous four matches in all competitions.
Both of their competitive defeats this term have occurred in their last two matches after losing to MK Dons and Queens Park Rangers in the EFL Cup and the league respectively.
Watford were involved in an eventful encounter at the weekend when goals from Ken Sema and Joao Pedro helped them come from behind on two occasions against QPR, but an Albert Adomah goal condemned Rob Edwards's side to a 3-2 defeat.
Despite losing on Saturday, the Hornets will be confident of claiming a win in midweek after winning two of their three home games this season.
Middlesbrough, meanwhile, began the season with a six-game winless run in all competitions, with their first five league matches yielding three points.
After playing out consecutive 2-2 draws, Boro lost for the second time this season in their most recent away encounter against Reading.
However, they bounced back at the weekend, beating Swansea City 2-1 to record their first win of the season, which leaves them in 18th place ahead of Tuesday's contest.
Riley McGree and Matt Crooks netted a goal apiece in their first half against the Swans, and although Joel Piroe halved the deficit in the 79th minute, Chris Wilder's side held firm to clinch three points.
After winning at home on Saturday, Boro will now attempt to win on their travels for the first time this term after collecting one point from their opening three away games.
Watford Championship form:
Watford form (all competitions):
Middlesbrough Championship form:
Middlesbrough form (all competitions):
Team News
Watford are expected to be without the services of Samuel Kalu, Tom Dele-Bashiru and Imran Louza, who are all sidelined with injury issues.
Rey Manaj could also miss out after being withdrawn in the first half against QPR, and if he is not fit enough for Tuesday's encounter then Yaser Asprilla could be given a starting place.
After the pair found the net on Saturday, Sema and Pedro have scored two goals each this season, and they will look to add to their respective tallies against Middlesbrough.
As for the visitors, they are unable to call upon Chuba Akpom, who is ruled out with a knee injury, while Duncan Watmore is a doubt after picking up an injury at the weekend.
After clinching their first win of the season on Saturday, Middlesbrough are expected to keep changes to a minimum, although Rodrigo Muniz could come into the lineup.
Crooks scored his second goal of the season against Swansea, and as one of two Boro players to score more than once this term, he will provide a goal threat from midfield on Tuesday.
Watford possible starting lineup:
Bachmann; Gaspar, Kabasele, Sierralta, Kamara; Kayembe, Choudhury; Sarr, Asprilla, Sema; Pedro
Middlesbrough possible starting lineup:
Roberts; McNair, Lenihan, Clarke; Jones, Howson, Mowatt, Crooks, Giles; McGree, Muniz