The Brazilian defender has missed the last two matches, victories against Dundalk and Manchester United, after he was forced off with a thigh injury during the home defeat to Leicester on October 25.
Arteta initially feared that Luiz would be out for "a few weeks" but the 33-year-old has resumed training and is available for selection.
"He is available to play and has been training well for the last few days and he will be involved in the squad," said Arteta.
"You will see some changes again tomorrow. We have to manage the minutes and exposure we give to the players. We have to think what we need now, as well as also looking ahead."
Arsenal are top of Group B after winning both Europa League matches so far, but Molde are also on six points having done the same.
The Gunners will be full of confidence after beating rivals United at Old Trafford in the Premier League for the first time in 14 years on Sunday.
Arteta thinks the game against the Norwegian club will be the toughest in the group to date.
"To go to a stadium like Old Trafford and play with the courage that we did, obviously it's a big plus in terms of confidence and belief. But now we have to play like that more regularly," said Arteta.
"We will need to because Molde will be really competitive tomorrow, as they have been in their two games so far, as we have to be ready.
"Their strengths are that they work really well as a team and they are strong physically and well organised and defensively hard to break down, with some creative attacking players who are dangerous in the final third. They are dangerous at set pieces as well.
"The table is really tight at the moment and it is probably the most difficult team we have faced in the competition."
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