Bottom-club Watford, who lie four points from safety, are aiming to extend a three-match unbeaten run in which they have only conceded one goal.
Chelsea, who are two points behind second-placed Manchester City, are targeting their fifth straight Premier League victory.
Team news
Isaac Success and possibly Etienne Capoue, who according to Watford head coach Quique Sanchez Flores is "not 100 per cent", could both be in contention to face Chelsea.
The Hornets remain unable to call on Troy Deeney, Ismaila Sarr, Danny Welbeck, Tom Cleverley and Domingos Quina, the latter of whom sustained a groin injury in the midweek EFL Cup defeat at Everton.
Chelsea have a quartet of players sidelined for the contest at Vicarage Road.
N'Golo Kante and Antonio Rudiger remain out with a groin and pelvic injury respectively, while Andreas Christensen and Ross Barkley are progressing, but not yet match-fit.
Did you know?
Chelsea, who won this fixture 2-1 last season, are aiming to secure back-to-back top-flight away victories over Watford for the first time.
The Blues have won 16 of their last 20 matches against sides starting the day bottom of the table, with their last such defeat coming back in October 2017, at Crystal Palace.
Watford are aiming to avoid remaining winless throughout their opening 11 matches of a league campaign for the first time, and becoming the first Premier League side to reach that point without a victory since QPR in 2012/13.
The Hornets are also seeking to avoid equalling their club record for the longest winless home run in the league. They are one result away from matching their 10-match sequence in 2004/05.
Match officials
Referee: Anthony Taylor. Assistants: Gary Beswick, Adam Nunn. Fourth official: David Coote. VAR: Mike Dean. Assistant VAR: Stephen Child.