The 22-year-old has made just one Premier League appearance this term, in stark contrast to the 23 appearances that he made in the previous campaign.
Tomori is keen to leave the west London club, either permanently or on loan, in order to play first team football and he’s attracted interest from Leeds United.
Lampard had been keen to send the former Derby defender out on loan but Tomori’s plans have been scuppered by injury to Denmark defender Christensen, according to the Sun.
The Dane sustained a knee injury in Chelsea’s 1-1 draw with Aston Villa and the club are anxiously awaiting results on the issue, with the medical team fearing the defender is set for a prolonged period on the sidelines.
The Dane has played his way back into contention this term and has provided back-up to first choice pair Kurt Zouma and Thiago Silva.
However, an injury lay-off would leave Chelsea short of options going into a hectic period in which European competition resumes alongside the FA Cup.
Chelsea are unlikely to seek defensive cover in the January transfer market after Lampard was handing around £220million to spend in the summer window.
The former Derby boss is under increasing pressure at Stamford Bridge after defeat against Man City on Sunday left his side with just one win in their last seven matches in all competitions.
Andriy Shevchenko, Thomas Tuchel and Max Allegri have all been linked with replacing Lampard.