Sheffield United are hoping Nick Montgomery (knee) and Sam Vokes (hamstring) can prove their fitness in time for the game.
Bjorn Helge Riise (hamstring) is out, but Ched Evans (knee) could feature.
MATCH PREVIEW
Sheffield United's midweek victory against Nottingham Forest - their first win of 2011 and their first under Micky Adams - was a massive and timely boost for the Blades in their battle to avoid dropping into League One.
Crystal Palace's win against Cardiff meant next-to-bottom United would have been left nine points adrift of safety had they not come from behind to win on Tuesday, which underlines how crucial that fightback by Adams' side could prove to be.
Buoyed by finally ending his 13-match wait for a win as Bramall Lane boss, Adams will be hoping his players can take another step in the right direction against a Watford side that are unbeaten in three matches and dealt Swansea's promotion bid a blow last time out.
Danny Graham's late equaliser against the Swans - the striker's 22nd goal of the season - secured Watford's third 1-1 draw in five matches. It also kept the Hornets in the top half of the table.
MATCH FACTS
Head-to-head
• United have won 19 and Watford 11 of the previous 42 meetings of these clubs.
• The winning team have kept a clean sheet in the last four matches between Watford and the Blades.
Watford
• Watford have scored one goal in five consecutive matches, and in seven of their last nine.
• They have drawn four of their last six games.
• The Hornets have failed to score in only one of their league outings in 2011.
Sheffield United
• United have won one, drawn four and lost nine of the 14 matches under boss Micky Adams.
• They have lost all but one of the 15 league games this season in which they have failed to score.
• They have lost 13 Championship matches by a single goal - more than any other team.
Source: BBC Sport
Source: BBC Sport