It means the match against the Hornets is going to be a big one for Lampard and getting his team selection right against the struggling Hertfordshire team.
The big question will be who he changes at the back, with the Blues defence poor in the 3-2 defeat to West Ham on Wednesday night.
However, Lampard won’t be able to call on Fikayo Tomori to come in, while Mateo Kovacic is set to miss the game with an Achilles’ problem.
“Fikayo is still not fit,” Lampard said. “He’s hopefully going to be training with us next week. He’s doing a lot of work, it’s just in terms of the last bit, getting him on the training pitch, it’s been tough.
“Kovacic is going to be out of this game. He hurt his Achilles in the West Ham game and we’ll miss him in this one and probably the next one, but hopefully he won’t be too long after that.”
Kurt Zouma should come into the starting XI for Andreas Christensen, while Marcos Alonso might come out of the team after his performance at the London Stadium.
Ross Barkley could keep his place in the starting XI, but up top it should be Olivier Giroud coming into the starting XI for Tammy Abraham.
Christian Pulisic has to start the match, while Willian has been in good form since the restart.
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Predicted Chelsea team (4-3-3): Kepa; Azpilicueta, Zouma, Rudiger, Emerson; Barkley, Kante, Mount; Willian, Giroud, Pulisic.