Borussia Dortmund issued an update on Konstantinos Karetsas at half-time of their Champions League match against Villarreal - and club officials have now spoken

Borussia Dortmund sporting director Nils-Ole Book says Konstantinos Karetsas was unable to speak after being stretchered off the pitch during their Champions League match against Villarreal. The summer signing from Genk signalled to the sideline that he could not continue midway through the first half, sitting down on the pitch and covering his face with both hands before lying supine.

Karetsas, 18, was making his Champions League debut. The crowd applauded him as he was carried off on a stretcher.

Dortmund described the issue as 'circulatory problems'. The club confirmed that he was going to the hospital for further examinations.

A statement shared on X at half-time of the match reads: "Konstantinos Karetsas had to leave the field due to circulatory problems. Kosta is doing well under the circumstances and is on his way to the hospital for further tests."

The former Dortmund captain, Mats Hummels, was working as a pundit at Westfalenstadion. He said of Karetsas on Amazon Prime Video: "When the doctors didn't even look at the legs, but only at the upper body, it sent shivers down my spine.

"We don't wish such a story on anyone. These are really nasty pictures that we had to see."

The club's sporting director Book then said of Karetsas on Sky after the match: "He was substituted due to circulatory problems. It came very suddenly, he sat down and was taken to the hospital for further examinations, where he is now.

"And of course we'll wait and see. Of course, that clouds the mood significantly."

He continued: "I went out with him, but he wasn't able to speak directly at that moment. Of course, we hope that it will get better very, very quickly and that it's nothing serious. But now, especially after the game, we don't have any new information yet."

Dortmund's managing director for sport Lars Ricken was shown on television shaking his head after the incident and also spoke afterwards. He described the situation as "very strange" and shared what was going through his head at the time.

"At first, I assumed that he might have some muscular problems. But then he didn't touch his thigh at all and was even carried down on a stretcher."

Ricken explained that the reasons Karetsas was having tests is "to rule out everything in the end." The former player continued: "We have to wait and see what the next few days will bring."

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Dortmund goalkeeper Gregor Kobel also spoke about the incident. He said: "Of course, it was super bitter that the second Greek had to leave the pitch straight away." The Switzerland international refers to fellow Greece international Giannis Konstantelias rupturing the anterior cruciate ligament in his left knee on Bundesliga debut 10 days ago.

Kobel continued: "I only heard that I think it was circulation. I hope and think that everything is OK, and hope that he will be fit again with us quickly."