MILLWALL will be boosted by the return of defensive duo Alan Dunne and Shane Lowry after they completed their three-match suspensions.
However, centre-back and captain Paul Robinson is unlikely to start as he continues to struggle with a thigh injury sustained prior to last week's win at Barnsley.
Spurs loanee Ryan Mason joined up with his new teammates for the first time on Monday and could be included in the squad. Long-term absentees Tamika Mkandawire (knee), Therry Racon (ankle) and Jordan Stewart (groin) remain on the treatment table.
Lions top-scorer Darius Henderson is likely to start against his former club and will be looking to continue his impressive form. Henderson, though, was sent-off last season against Watford whilst playing for Sheffield United.
Watford are expected to have central midfielder Jonathon Hogg available again after the former Aston Villa man shook-off a minor knee injury.
New signing Alex Kacaniklic is match-fit after the midfielder joined the Hornets on loan from Fulham last week. Sean Dyche will still be without central defender Martin Taylor (broken toe) and midfielder Stephen McGinn (knee).