The 25-year-old has spent the past six weeks in his native Brazil, where he underwent surgery to repair the anterior cruciate ligament damage suffered in the Reds' Carling Cup quarter-final win at Chelsea in November.
Lucas, who is walking with the aid of crutches, will still miss the remainder of the campaign but believes his recovery is on course.
He told the club's website, www.liverpoolfc.tv: "I am still a long way away, but the knee is getting better and the rehab is going well.
"I have to make sure I complete a perfect rehab and be back as soon as possible.
"The next stage is to get the knee moving and in the next few weeks I'll start to walk again.
"Hopefully in a month's time I'll start in the gym and my programme and be able to work with weights.
"When you're on crutches you cannot do too much, so I can't wait to start my programme and get in the swimming pool and things like that.
"The physios and the doctors have told me the rehab is going well and progressing well. I am doing everything I can to help my knee recover."