Lloyd Doyley has been ruled out with a neck injury and joins fellow defender Joel Ekstrand and midfielder Sean Murray (both knee) on the sidelines.
Adlene Guedioura, who started the 2-0 win at Brighton last weekend which secured promotion, is also missing as his loan from Crystal Palace has expired.
The Hornets need to match or better Bournemouth’s result at Charlton to be crowned champions.
Sheffield Wednesday head coach Stuart Gray will select his starting XI from an unchanged squad.
Striker Will Keane (ankle), who will return to parent club Manchester United next week, is pushing for a start after stepping off the bench in last week’s home defeat to Leeds.
Midfielder Jose Semedo played the full 90 minutes last week following a foot problem and is likely to continue.
But skipper Glenn Loovens (hamstring), fellow defender Kamil Zayatte (fractured cheekbone) and midfielder Filipe Melo (foot) remain sidelined.