Tomori is closing in on a return to action after suffering a muscle injury in training ahead of the Premier League restart.
The 22-year-old centre-back was back in training this week but remains unavailable for this weekend’s fixture.
“Fikayo is still not fit. He’s hopefully going to be training with us next week,” said Lampard.
“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.”