Borussia Dortmund have completed the signing of Konstantinos Karetsas from Belgian club Genk, with the move confirmed on 3 August 2026. The 18-year-old Greece international has signed a five-year contract running until June 2031. Dortmund are paying a guaranteed fee of €30m, which can rise to around €32m with add-ons, making Karetsas the second most expensive signing in the club's history behind only Ousmane Dembélé. Genk have also secured a 10% sell-on clause covering any future transfer profit.
Dortmund's football leadership see Karetsas as a long-term successor to Julian Brandt, who has left the club for Ajax. Managing director of sport Lars Ricken said: "With Kos, we're adding a player to Borussia Dortmund who, at just 18 years of age, already possesses tremendous talent." Sporting director Nils-Ole Book added that Karetsas "will enrich our team with his creativity and footballing intelligence," pointing to his knack for finding solutions in tight spaces in the final third. A left-footed attacker who likes to cut inside from the right, Karetsas offers close control, agility and vision that head coach Niko Kovač has been short of among his midfield options.
For Genk, this is a club-record departure. Karetsas joined their academy at the age of six and worked his way through to the first team, going on to make 92 appearances and contribute six goals and 23 assists for the club. His sale continues a run of lucrative academy exits for Genk, who are reported to have brought in around €185m from player sales over the past three seasons, underlining the strength of their youth system even as they lose one of its brightest products.
Karetsas was one of the most productive creative players in Belgium's top flight last season. Playing mainly off the right and through the middle for Genk, he made 34 appearances in the Belgian Pro League and set up ten goals for teammates, without scoring himself, regularly ranking among the division's leaders for chances created. That end product, built on close control and quick decision-making rather than goals, is what drove his rapid rise up the price list, with reported interest from clubs including AC Milan and Paris Saint-Germain earlier in the transfer window before Dortmund won the race.
At Dortmund, Karetsas will compete for one of the attacking-midfield or right-wing spots behind striker Serhou Guirassy, with Kovač aiming to work him into the squad before the season starts in earnest. He is set to join up with his new teammates for the remaining pre-season friendlies against Arsenal and Roma, ahead of Dortmund's campaign proper opening in the German Supercup against Bayern Munich on 22 August. Given his age and the size of the fee, he is more likely to be eased in than thrown straight into the starting eleven, but the scale of the outlay shows how highly the club rate him.