The Chelsea manager is under increasing pressure following his side’s dramatic collapse of form.
The 2-0 defeat at Leicester has prompted intense speculation about his future, with a host of big-name candidates linked with the job.
Lampard insists he is solely focused on improving performances on the pitch and admits levels have dropped.
“It was definitely slow and sluggish (against Leicester), he said. “One of the things that set us out as a team last year was our energy and in parts this season. The energy to beat Leeds to beat Seville takes a lot of energy and it’s a part of the team that I feel proud of when I put out a team and it shows that.
“We did that last year and managed to get to fourth position. When I see it come off I have to call it out and we have to work in training to get it better because you cannot play if you don’t run first. I don’t want to explain exactly what the reasons are for each individual if they are not at it on one day. There can be a multitude of reasons for it.
“As a group we need to get back to the energy that we were when we were winning games.”
Timo Werner could be handed his first start since the last round against Morecambe, while Billy Gilmour could also come in.
N’Golo Kante has been trying to overcome a hamstring issued that ruled him out of Leicester, but Lampard may prefer to wait until Wolves midweek to bring the midfielder back.
Olivier Giroud also missed Leicester with a knock on his ankle, but should be fit to return here.
“Luton’s going to be a tough challenge,” Lampard added. “They are going well in the Championship, they are a good team, it’s the FA Cup, we know what comes with it. So we’ll pick a team to try to win the game and get us through to the next round.”
Chelsea predicted XI: (4-3-3) Arrizabalaga; Azpilicueta, Zouma, Christensen, Chilwell; Havertz, Jorginho, Mount; Hudson-Odoi, Abraham, Pulisic
Injury list: N’Golo Kante (thigh)