Peterborough have a doubt over midfielder Lee Frecklington, who was replaced at half-time against Sheffield United after picking up a calf injury.
Winger Chris Whelpdale remains sidelined with a groin problem.
MATCH PREVIEW
Struggling Peterborough are heading for League One, and Watford could join them unless they arrest an alarming recent slump.
Their defeat at home to Swansea on Tuesday was the Hornets' third consecutive loss and left them only two points above the relegation zone.
They will see a home match against the division's bottom club as the perfect opportunity to end that run and pick up three much needed points.
Posh beat promotion chasing Sheffield United in midweek to record only their sixth win of the season. But all of those wins have come at home; they are the only side not to win away in the Championship this season.
MATCH FACTS
Head-to-head
• Peterborough have won the last two matches between these clubs.
Have your say on this match
• The Hornets have won one of their last five home league games against Peterborough.
• Posh, who beat Watford earlier this season, last did the double over Watford 35 years ago, when both clubs were in the old Third Division.
Watford
• Watford are enduring their worst losing run since five in a row between October and November 2008.
• The Hornets have gained one point out of a possible 12 since beating Bristol City 2-0 at Vicarage Road on 9 February.
• They have trailed 1-0 at half-time in each of their last four matches.
Peterborough
• Peterborough, who won their last game, have not recorded back-to-back victories at Championship level since 1994.
• They have lost their last seven away games and failed to score in the last four of them.
MOST RECENT MEETING
Peterborough 2-1 Watford (19 December 2009)
Peterborough scorers: Frecklington 9, Geohaghan 78.
Watford scorer: Eustace 49.
Source: BBC Sport
Source: BBC Sport