Dortmund pay 30 million euros for Karetsas, and only Dembele has cost them more
The 18-year-old Greece international arrives from Genk on a deal to 2031, after a season in which only one player in Belgium created more goals than he did.
Aug 3, 2026
Borussia Dortmund have signed Konstantinos Karetsas from Genk, handing a five-year contract to an attacking midfielder who does not turn 19 until November. The deal was announced on 3 August and runs to June 2031, and the fee reported in Germany is around 30 million euros guaranteed, with bonuses that can push it past 32 million.
At that price only one player has ever cost Dortmund more.
Where this sits in the club’s history
Ousmane Dembele, bought from Rennes for 35 million euros in 2016, remains the record. Sebastien Haller cost 31 million in 2022. If Karetsas triggers his bonuses, he goes past Haller and sits second on a list Dortmund have historically been careful about, because their model has been to buy young, develop, and sell at a profit rather than to pay top of the market.
Genk have protected themselves accordingly. Reports in Belgium and Germany put a ten per cent sell-on clause in the agreement, so if this works the way both clubs expect it to, Genk get paid twice.
What Dortmund are buying
Karetsas is left-footed, plays as an attacking midfielder and has been in the Belgian top flight since he was 16 years and eight months old, which is a debut age that usually comes with either a very good academy or a very brave coach. Last season he registered 11 assists in the Jupiler Pro League, second-most in the division, and added two goals and five assists in the Europa League.
Assist numbers can flatter a player in a team that attacks constantly. These do not look like that kind of return. Eleven league assists and another seven goal involvements in Europe, all of it before his 19th birthday, is a serious body of work for a teenager.
He has 10 caps for Greece and three goals, having made his senior debut against Scotland in March 2025. He was born in Genk to Greek parents who had settled in Flanders, grew up in the club’s academy with a three-year spell at Anderlecht in between, and plays for Greece.
The squad he walks into
Dortmund finished second in the Bundesliga last season, behind a Bayern Munich side that wrapped up the title on 19 April with four games to spare and scored 122 league goals doing it. Second place in that context was respectable and nowhere near close, and closing a gap of that size is not usually done by signing an 18-year-old.
What it does do is give the squad a creator with years in front of him rather than a short-term fix, which is the trade Dortmund keep making. Some of those bets have paid enormously, Jude Bellingham being the obvious one. Others have quietly not.
Lars Ricken, the club’s managing director for sport, framed the signing around the player’s talent and how young he still is. Karetsas talked about the club being a special one and the pride of wearing the black and yellow. Neither man said anything that will be remembered if it goes wrong, which is how these announcements work.
The bit that decides it
Belgian football to the Bundesliga is a jump, but it is one of the better-mapped routes in Europe, and Dortmund’s coaching staff have taken teenagers through it before. The questions are the ordinary ones. Can he handle being pressed harder and faster every week, and can he get on the ball in a league where the space he enjoyed at Genk will not be there?
He has until June 2031 to answer. Dortmund have paid enough that they would like it sooner.