The Gunners are taking on the Spanish side, and old boss Unai Emery, as they seek to win the competition and book a place in next season's Champions League.
The first leg is on Thursday in Spain, and manager Mikel Arteta will be delighted if he can call on Luiz for the game.
The Brazilian has not played since March 21, when he had surgery on a knee injury.
Arteta will assess Luiz in training before deciding whether he can start the game or is only fit for a place on the bench.
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