Mauricio Pochettino's side recorded three straight wins, two of which were in the Premier League, ahead of their trip to Boro for the first leg of their EFL Cup semi-final, but they lost 1-0 at the Riverside Stadium.
The Blues are currently 10th in the Premier League table, 12 points behind fourth-placed Arsenal, but they are now just three points from Brighton & Hove Albion in seventh.
Here, Sports Mole rounds up Chelsea's latest injury and suspension news ahead of their clash with Fulham, who are 13th in England's top flight.
Christopher Nkunku
Status: Out
Type of injury: Hip
Possible return date: Unknown
Nkunku has only just returned from a serious knee injury, which delayed his Chelsea debut until December 24, but he is now suffering with a hip problem, and it is unclear when the forward will be available again.
Ben Chilwell
Status: Major doubt
Type of injury: Hamstring
Possible return date: January 13 (vs. Fulham)
Chilwell is in the latter stages of his recovery from a hamstring issue, and there is a slight chance that the left-back could be back in the squad for this contest.
Wesley Fofana
Status: Out
Type of injury: Knee
Possible return date: Unknown
Fofana is not expected to be available for selection until next season, with the centre-back being forced to undergo an operation on a severe knee injury over the summer.
Trevoh Chalobah
Status: Out
Type of injury: Thigh
Possible return date: Unknown
Chalobah is still struggling to overcome a thigh problem, and the centre-back will again be unavailable for selection against Fulham this weekend.
Carney Chukwuemeka
Status: Major doubt
Type of injury: Knee
Possible return date: January 13 (vs. Fulham)
Chukwuemeka has been out since October with a knee problem, but the midfielder is now back in training and has not yet been ruled out of this weekend's contest.
Lesley Ugochukwu
Status: Out
Type of injury: Hamstring
Possible return date: Unknown
Ugochukwu suffered a hamstring injury during Chelsea's loss to Wolverhampton Wanderers last month, and the midfielder is not expected to be back until February at the earliest.
Reece James
Status: Out
Type of injury: Hamstring
Possible return date: Unknown
James is currently on the sidelines recovering from a hamstring operation, and it is unlikely that the Chelsea captain will be back on the field until the end of March.
Robert Sanchez
Status: Out
Type of injury: Knee
Possible return date: January 31 (vs. Liverpool)
Sanchez remains unavailable due to a knee injury, but the club's number one goalkeeper has a chance of being available for selection before the end of the month.
Marc Cucurella
Status: Out
Type of injury: Ankle
Possible return date: March 2 (vs. Brentford)
Cucurella is currently battling his way back from a severe ankle problem, and it is unlikely that the Spaniard will be available until the start of March at the earliest.
Romeo Lavia
Status: Out
Type of injury: Thigh
Possible return date: Unknown
Lavia made his Chelsea debut in December against Crystal Palace after recovering from an ankle issue, but the summer arrival is currently out with a thigh problem, and it is unclear when he will be available again.
Nicolas Jackson
Status: Out
Reason of absence: International duty
Possible return date: Unknown
Jackson will represent Senegal at the Africa Cup of Nations, and the striker will not be available for selection until his country have been knocked out or the competition has finished.
Benoit Badiashile
Status: Out
Reason of absence: Unknown
Possible return date: Unknown
Badiashile was again absent against Middlesbrough due to an unknown issue, and the centre-back has also been ruled out of the clash with Fulham this weekend.
CHELSEA'S SUSPENSION LIST
Chelsea have no players suspended for this match.