Back-up goalkeeper Rene Gilmartin is the only injured player at Vicarage Road so academy keeper Jonathan Bond will again be on the bench as cover for Scott Loach.
Gilmartin deputised for Loach in the recent Carling Cup win at Aldershot but picked up a knock in the victory and is not yet fit to return.
New signing Troy Deeney is likely to be on the bench again as he waits for his full debut following his £500,000 switch from Walsall.
Defender Dale Bennett has returned from injury to be on the bench for the last two games.
The Hornets’ last trip to the KC Stadium saw the Tigers romp to a 4-1 win in the Championship play-off semi-final of 2008.