Middlesbrough boss Tony Mowbray will make a series of late checks before naming his team.
Full-back Justin Hoyte and midfielder Nicky Bailey were both substituted during Tuesday night's 3-1 victory at Doncaster and are currently being assessed.
Hoyte tweaked a hamstring while Bailey sustained a calf problem.
Midfielder Kevin Thomson suffered a hamstring injury during the 2-0 defeat at Nottingham Forest on October 18, and his condition too is being monitored.
Defender Seb Hines left the City Ground with swelling to his knee and like Thomson, will be checked before Mowbray makes a final decision.
Boro's win at Doncaster was just their second in eight league games and lifted them back into third place in the league.
Watford are likely to remain unchanged once again as they look for a third successive victory.
Sean Dyche named the same line-up for Tuesday's 1-0 win over Brighton as the side who beat Peterborough 3-2 last weekend, ending a run of four successive defeats.
Troy Deeney bagged the winner against the Seagulls within 104 seconds of being introduced from the substitutes' bench and will be pushing to start at the Riverside, but Dyche is likely to keep faith with his XI.
On-loan winger Michael Kightly returned from his hamstring injury as a second-half substitute in midweek and will again be part of the squad travelling north for the 5.20pm kick-off.
Striker Craig Beattie will again be assessed as he looks to overcome a hamstring injury of his own, but skipper John Eustace (back) and defender Lloyd Doyley (thigh) are likely to miss out once more and will now look to return after the forthcoming international break.
Centre-back Martin Taylor is sidelined for around 10-12 weeks with his dislocated collarbone, while midfielder Stephen McGinn is making good progress with his rehabilitation from a long-term knee injury.