The Blues lost the central midfielder early on against Man United last week and Lampard confirmed the extent of the injury afterwards.
“It’s an adductor injury. We will have to assess it, scan it,” he said.
“But it doesn’t look great.”
Lampard has already stated that he is hoping the midfielder will be back in around three weeks’ time.
“N’Golo [Kante] is not fit. He has got a muscle injury [adductor], similar to the one he came off recently against Arsenal with. Hopefully he will be [back] in three weeks, something around that.”
Loftus-Cheek’s long wait for a comeback could soon be over. The midfielder is yet to feature under Frank Lampard after picking up an injury in the post-season friendly against New England Revolution.
He was however included in the squad for the game against Tottenham at the weekend but was an unused substitute.
Frank Lampard left the midfielder out of his matchday squad to face Bayern however, and he could be in line to return against Bournemouth on Saturday.
It is back to the business of the Premier League for Chelsea on Saturday as they look to shake off the disappointment of defeat in the Champions League round of 16 first leg against Bayern Munich.
Goals from Serge Gnabry (x2) and Robert Lewandowski saw the Blues lose 3-0 to the German giants. A red card for Marcos Alonso and the suspension of Jorginho make the task at the Allianz in three weeks time even harder.
But the Blues will be looking to bounce back quickly as they look to pick up three points in order to consolidate themselves in the top four of the Premier League.
Chelsea face a trip to the south coast to take on AFC Bournemouth.
CHELSEA STRIKER OLIVIER GIROUD HAS SPOKEN ABOUT SERGE GNABRY
Here’s the latest Chelsea injury news and expected return dates ahead of that game.
Chelsea have been handed a fresh blow over Tammy Abraham.
Following two quickfire goals from Bayern after half-time, Abraham was introduced with half an hour remaining.
He looked set to go through on goal after the visitors had added a third, but was challenged by Jerome Boateng, with both players staying down after the tackle.
Abraham shook off the blow to carry on, but it looks as if it may have caused more damage for the England international.