Brighton boss Roberto de Zerbi has confirmed a double injury blow for Tariq Lamptey and Ansu Fati.
Both players were forced off during the win at Nottingham Forest on Saturday.
"Fati and Lamptey are injured. We have lost them for a long time I think," said De Zerbi ahead of Thursday's Europa League clash with AEK.
"The focus is on the players who can play tomorrow.
"We will have to compete. I don't know if we will win, but we will fight to win the game for sure."