Lucas is back in training after picking up a thigh problem during the game against Manchester City in August.
The injury was a blow for Lucas after the Brazilian missed a large chunk of last season with a serious knee ligament problem.
Liverpool are unwilling to take any risks with his fitness, but he should get a run-out with the second string against Boro as he works his way back to match sharpness.
Reds assistant manager Colin Pascoe is happy to see Lucas back and he admits they will make a late decision on whether or not to play him against Boro.
"The next step is getting his strength up in training and hopefully he can get 45 minutes in the reserve game on Friday," Pascoe told the club's official website
"But we'll assess him, see how he is in the next couple of days, and if he feels fine himself, then he could possibly have 45 minutes on Friday.
"It's fantastic to see Lucas back in training. He's a good player and it's nice to get him back.
"He's been unfortunate with a lot of injuries. I know that's part and parcel of football but it can get you down and it's nice to see Lucas with a smile on his face.
"He's a great professional. He's done his recovery and rehab. When you're injured, you can't wait to go and play football again and sometimes you can't see a light at the end of the tunnel, but Lucas has kept his head down, worked hard and he's looking good in training."