Bristol City will be without defender Jamie McAllister for the game at Vicarage Road.
He was the victim of a crunching tackle in Friday's defeat against Leicester, which left him with a fractured rib and a badly bruised calf.
MATCH PREVIEW
Watford boss Malky Mackay was pleased with his team's display in the 1-1 draw against Reading on Saturday, but the Royals' second-half equaliser left Mackay's men without a win in six matches.
At times in that game the Hornets showed why they were in the thick of the promotion race only weeks ago, and their fans will be hoping they can finally get back to winning ways on Tuesday evening.
Not only would that be a much-needed boost for Watford, it would also pile more misery on struggling Bristol City, who are only two places above the relegation zone after a run of only one win in eight league matches.
The Robins seemed to have secured a useful point at in-form Leicester last time out, but left the East Midlands empty-handed after Martyn Waghorn's winner for the Foxes two minutes into injury time.
MATCH FACTS
Head-to-head
• City have won 34 and Watford 27 of the 88 previous matches between these clubs.
• The Robins have won on two of their last three visits to Vicarage Road.
Watford
• Watford are without victory in seven league and cup games.
• The Hornets, who have drawn their last two league matches, have not drawn three in a row since March 2008.
• They are the only team yet to have had a player sent off in the Championship this season.
• If selected, John Eustace will be making his 100th league appearance for the club.
Bristol City
• City have lost five of their last seven league games.
• They have lost 11 games this season against current top-12 clubs.
• Goalkeeper David James is set to face the club where he started his career.
Source: BBC Sport
Source: BBC Sport