Olympiacos, Kostoulas' current team, is hesitant to let him go. They want to include a clause in the deal that would give them a share of any profit if Kostoulas is sold in the future. Kostoulas has been playing for Olympiacos' first team this season and has scored seven goals and provided one assist in 35 games.

Kostoulas broke into the first team this season, and his performances have been impressive. Abdallah Sima, the player Brighton would get in exchange, is currently on loan with a French team called Brest. He has not played for Brighton since joining the club in 2021.