Crystal Palace beat Chelsea 2-1 last weekend despite having not scored a goal in seven games before the match. Watford are now sitting above Chelsea after they beat Arsenal at Vicarage Road, fighting back from being 1-0 down to win 2-1 thanks to a late winner from Tom Cleverley.
Antonio Conte's woes have deepened with a number of players out injured, but they can't afford to drop any more points if they are to have any hope of catching league leaders Manchester City.
Alvaro Morata returned from his hamstring injury to face Roma on Wednesday but N'Golo Kante, Victor Moses and Danny Drinkwater remain out.
Kante is having another scan on his hamstring to assess his injury but he could be out until after the November international break. Victor Moses also has a hamstring problem after coming off in the first half against Crystal Palace.
He could also be out for three more weeks yet with Davide Zappacosta likely to fill in his place. Danny Drinkwater has still yet to make his debut and is needing more time to get over his calf injury.
Chelsea's 3-3 draw against saw David Luiz withdraw in the second half due to a minor calf injury while Conte also said that Tiemoue Bakayoko has a groin complaint. Gary Cahill also got a minor head injury but he will be available for selection.
Baba Rahman remains at Stamford Bridge but isn't part of the club's Premier League or European squad due to a knee injury. He is expected to return by late November. Conte address the situation around injuries at his press conference on Friday afternoon.
"I have many doubts. I hope in the next 24 hours to try and recover some players," Conte said. "That could be [the case that Fabregas is the only fit midfielder]. For sure, tomorrow the game will be very tough because Watford are a good team, in a good position in the table.
"They have enthusiasm. But we play at home after two defeats in the league, and we want to come back to win.”
Chelsea have no suspensions for the match against Watford. David Luiz returned from a three-match ban against Crystal Palace after getting sent off against Arsenal a month ago.
He also suffered a fractured wrist during that match against the Gunners but he is playing through the minor injury.
POTENTIAL STARTING LINE-UP
Chelsea will need to assess the fitness of their players who are tiring during a busy run of fixtures. Conte has complained about the number of injuries he is getting and may have added a few more names after the draw with Roma.
Conte has hinted at switching systems from his preferred 3-4-3 since his side's embarrassing loss to Crystal Palace but 3-5-2 is the most likely long-term option after it was used in the Champions League against Roma.
Chelsea may reintroduce some of their benched players against Watford with most of their players having played two games in a row. Willian, Pedro and Antonio Rudiger might be looked to with the view of freshening things up.
WATFORD TEAM NEWS
Nathaniel Chalobah had been playing well in Watford colours since his £6 million move from Chelsea in the summer but he has had to have an operation on a fractured kneecap and he faces a long spell on the sidelines.
Sebastian Prodl and Younes Kaboul are big fitness doubts with the former having a hamstring injury, while the latter has a knee problem. Craig Cathcart is also out until 2018 with a knee injury.
BEST OPTA MATCH FACTS
Watford haven’t won a competitive game against Chelsea at Stamford Bridge since May 5th 1986. The Hornets enjoyed a 5-1 victory in their final top-flight game of the 1985-86 season, thanks to goals from David Bardsley (2), Brian Talbot (2) and Colin West.
Chelsea beat Watford both home and away in the Premier League last season by a single goal margin and both matches saw them score the winning goal in the 87th minute or later.
Chelsea have already lost three of their opening eight Premier League games to the 2017-18 season. The last time a team lost this many of their opening eight league games and still won the top-flight title were Manchester United in 1966-67.
Marco Silva has won 10 points from a possible 12 away from home in the Premier League as a manager this season (W3 D1 L0). In 2016-17 while at Hull City, he saw his side pick up just two points from nine away games in the Premier League (W0 D2 L7).
TV CHANNEL & KICK OFF TIME
The match is being televised on Sky Sports at 12:30 BST on Saturday afternoon.