Borussia Dortmund Star Konstantinos Karetsas Hospitalized After Collapsing in Champions League Debut

Borussia Dortmund teenage star Konstantinos Karetsas was hospitalized after slumping to the turf 25 minutes into his UEFA Champions League debut against Villarreal, the German club announced.

“Konstantinos Karetsas had to leave the field due to circulatory problems,” Dortmund said in a statement late on Tuesday. “Kosta is doing well under the circumstances and is on his way to the hospital for further tests.”

During the match, the 18-year-old Greek prospect passed the ball to a teammate, signaled his distress to the referee, and sat on the grass. Karetsas received medical treatment while lying down before being carried away on a stretcher. The score was 0-0 at the time in a game that ultimately ended in a 3-2 victory for Dortmund.

“I hope and I think that everything is OK, and I hope that he’s back and fit with us soon,” Dortmund goalkeeper Gregor Kobel told a broadcaster.

Karetsas and his Greek teammate Giannis Konstantelias were marquee signings for Dortmund in the off-season. Former Belgium youth international Karetsas joined for $34.9m from Genk, while Konstantelias arrived for $30.2m from PAOK.

Karetsas was previously a target for numerous clubs following an impressive campaign at Genk last season, where he provided 11 assists in 28 Jupiler Pro League appearances. He is signed to a five-year contract running through June 2031.

“With his creativity and game intelligence, Kos will enrich our team,” Dortmund sporting director Ole Book said. “He is technically very skilled and has the ability to find quick solutions in tight spaces, especially in the final third.”

Having previously represented Belgium’s youth teams, Karetsas chose to represent his parents’ country and made his debut for Greece in March 2025, scoring three goals in 10 international appearances. Meanwhile, teammate Giannis Konstantelias suffered a season-ending ACL injury last month during his Bundesliga debut.