Derby defender Russell Anderson, who has only recently returned to first-team contention after two months out with a groin problem, will miss the game after suffering a hamstring injury playing for the reserves this week.
It is hoped this absence will only be a short one and Anderson could resume training within the next 10 days.
Midfielder Stephen Pearson has returned to training after missing the last three matches with a knee injury and could be included in the squad.
Luke Moore has extended his loan spell from West Brom and could be restored to the starting line-up.
However, fellow forward Ryan Noble has returned to Sunderland following his month-long stay at Pride Park.
Watford manager Malky Mackay is hoping to have top scorer Danny Graham available for the trip.
Graham only lasted an hour of the 2-0 defeat to Scunthorpe last weekend before limping off with a back injury and the former Middlesbrough striker has not trained all week.
Graham - who had a spell on loan at Pride Park in the 2005/06 season - could still make it alongside partner Marvin Sordell, who is fit despite also going off against the Iron.
Full-back Lee Hodson also has a back injury and is a doubt while Scottish winger Don Cowie is still unavailable with his knee injury.
Midfielder Ross Jenkins has recovered from an ankle injury and is in line to be involved along with 19-year-old Matthew Whichelow, who made his debut as a late substitute last week.