This will be Millwall's first match in over two weeks after their fixture at Luton Town was called off last weekend.
Match preview
Despite being a fair way off the pace of runaway top two Norwich City and Sheffield United, Watford are well in the playoff hunt.
Slaven Bilic's side sit comfortably in fourth after amassing 17 points from a possible 24 either side of the brief World Cup break for the EFL.
Their form at home has been solid in recent weeks, especially in defence, where they have conceded just once in their last four games.
The Hornets are unbeaten at Vicarage Road against their upcoming opponents in the last six head-to-head's too (five wins), keeping four clean sheets in the process.
However, Bilic did lose 3-0 at the Den in the reverse fixture during his first few weeks in charge back in October, so he and his side will look to put that right.
A Tom Bradshaw hat-trick saw them romp to success that day, but Millwall may find it slightly trickier here.
Even though they are just two points off playoff places with a game in hand, only Huddersfield Town have picked up fewer points on the road in the Championship this season.
Any continuation of the form which has seen them pick up just two wins from 11 away games could be what scuppers their dream of promotion to the Premier League, especially considering their home form alone would have them competing near the automatic spots.
Gary Rowett's side have drawn a blank in three of their last four away matches while they have kept just one clean sheet from their previous 16 on their travels.
The postponement of their match at Luton last week also meant they have lost a bit of ground in what is a very close battle for the playoffs.
Watford Championship form:
W
L
W
D
D
W
Millwall Championship form:
L
D
D
W
L
D
Millwall form (all competitions):
D
D
W
D
L
D
Team News
Hamza Choudhury will be out for another month at least after he went off early for Watford against Hull City two weeks ago.
Keinan Davis, Matthew Pollock and James Morris were all struck down with a virus and missed a few days of training this week, but Bilic expects to have more or less the same squad he had available against Huddersfield last week.
Tom Cleverley, Imran Louza and Kortney Hause all remain out for Watford.
Millwall boss Rowett may be able to call upon the services of Ryan Leonard and Benik Afobe again after the duo missed the last few months with injury.
However, the fitness of Callum Styles will be assessed as the Hungarian international missed their last match against Wigan Athletic.
Watford possible starting lineup:
Bachmann; Ngakia, Kabasele, Cathcart, Kamara; Sema, Bacuna, Dele-Bashiru, Joao Pedro, Sarr; Davis
Millwall possible starting lineup:
Long; McNamara, Hutchinson, Cooper, Wallace; Mitchell, Saville, Flemming, Voglsammer, Styles; Bradshaw
We say: Watford 2-0 Millwall
Form and recent history between the sides suggests Watford should enjoy a relatively trouble-free victory.