The visitors, meanwhile, will be looking for an upturn in fortunes after failing to win any of their last three matches.
Match preview
Watford missed the chance to record a fourth consecutive victory when they played host to Coventry City on Saturday.
A close-fought contest was decided by a Viktor Gyokeres's second half strike, which condemned Watford to a narrow 1-0 defeat.
The result represented the first time Watford have failed to find the net in a Championship home game since December 2020.
Despite losing at the weekend, Slaven Bilic's side will be confident of claiming all three points on Tuesday after winning three of their last four league meetings with Reading.
With two points separating them from the playoff places, the Hornets could potentially move into the top six if they win and results elsewhere go in their favour.
Reading head into Tuesday's contest in poor form after winning only one of their last eight games, while they are also winless in three matches.
In their most recent encounter, Reading thought they had done enough to take a point from their home meeting with Preston North End when Lucas Joao levelled from the spot in the 71st minute to cancel out Ched Evans's opener.
Unfortunately for the Royals, they were unable to hold on for a draw as Evans scored his second goal of the game to secure Preston a 2-1 victory.
Although Paul Ince's side are currently struggling for wins, they find themselves in 12th place and only three points adrift of Tuesday's opponents.
While Reading will be looking to move level with Watford, they may be content with a point as they have lost six of their nine away games this season.
Watford Championship form:
W
L
W
W
W
L
Reading Championship form:
L
L
W
L
D
L
Team News
Watford are without the services of Imran Louza, Jeremy Ngakia, Tom Cleverley and Rey Manaj, who are all sidelined with injury issues.
Hassane Kamara and Francisco Sierralta are both ruled out through suspension due to an accumulation of yellow cards.
As a result, Bilic could be forced into a defensive reshuffle, which could see Edo Kayembe operate as a makeshift left-back, while Christian Kabasele may come into the side to partner William Troost-Ekong in central defence.
Meanwhile, Reading are unable to call upon Sam Hutchinson and Femi Azeez due to hamstring problems, while Naby Sarr and Scott Dann will also miss out through injury.
Ovie Ejaria dropped down to the bench for Saturday's defeat, but he could return to the side for Tuesday's contest.
After coming off the bench to score from the spot against Preston, Joao may be rewarded with a place in the starting lineup
Watford possible starting lineup:
Bachmann; Gaspar, Troost-Ekong, Kabasele, Kayembe; Gosling, Choudhury; Sema, Pedro, Sarr; Bayo
Reading possible starting lineup:
Lumley; Yiadom, McIntyre, Holmes; Hoilett, Loum, Hendrick, Baba; Ince, Ejaria, Joao