The defender had to bring his left shoulder back in after landing hard in Colchester's draw with City 11 days ago.
But he is back in training and hopes to convince Graham Alexander that he is ready to face Morecambe in Saturday's second round match.
Alexander said this afternoon: “Today was his first main session and he was fully integrated. Let's see from his movements how he is and how he feels.
“He looked okay playing against other players, but playing a match is a completely different story and we don't want that to happen again.
“I'm going to let Lewis lead. We're not putting immense pressure on him.”
City's manager revealed that Luiz was “desperate to play” in the postponed home game against Accrington, but decided it was too early for a wing-back.
Mr Alexander added: “His shoulder straightened back up and the test results weren't too bad.
“Lewis had a couple of options regarding the recovery process.
“He wanted to get his fastest horse back because he feels strong and moves well, but there's always the possibility of it happening again.
“As a player, all you can do is leave your body, and if your body says it’s okay, it’s okay.
“In his head, he knows he's going to be OK and he's determined to get back in the game.”
Alex Pattison and Aiden Baldwin have been with the squad all week, with Antoni Sarcevic and Ciaran Kelly out for part of training.
