On-loan defender Martin Taylor is likely to make his Watford debut, as could recent signing Stephen McGinn.Winger Will Buckley will not feature as he has suffered a thigh strain, but striker Danny Graham is expected to be fit after a slight knee injury.
Sheffield United's new signing Nyron Nosworthy will go straight into their squad, but Tony Kallio did not complete his loan move in time to play.
Marcel Seip (hamstring) and Andrew Taylor (hamstring) are both ruled out.
MATCH PREVIEW
Watford are looking to halt an alarming slide down the table which has seen Malky Mackay's team drop from sixth to 17th in the space of two months.
The struggling Hornets have not won in six matches and last registered a victory when they beat Queens Park Rangers at home in December.
Ominously for Watford, Sheffield United have been far from kind to struggling teams this season. Eight of the Blades' 11 league victories - and three of their four away wins - have been against clubs in the bottom seven.
United remained in the top six despite Saturday's 3-1 defeat against West Bromwich Albion, which ended a three-match winning run.
MATCH FACTS
Head-to-head
• Sheffield United are unbeaten in four league games against Watford, and are vying for a fourth successive league victory over them.
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Watford
• Watford have played 29 matches this season - fewer than any other Championship side.
• A third consecutive loss would condemn the Hornets to their longest run of defeats since they lost five in a row between October and November 2008.
Sheffield United
• United have scored more goals in the last 15 minutes of Championship matches than any other club this season (13).
• Leading scorer Darius Henderson is set to play against his former club, as could Jordan Stewart and Lee Williamson.
MOST RECENT MEETING
Sheff Utd 2-0 Watford (15 August 2009)
United scorers: Ward 12, Evans 63.
Source: BBC Sport
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