Dortmund's Konstantelias out for several months with ACL injury

Borussia Dortmund midfielder Giannis Konstantelias faces several months on the sidelines after suffering a cruciate ligament tear in his left knee during his Bundesliga debut against Hamburg, the club announced on Sunday.

The 23-year-old Greece international sustained the injury in a midfield challenge in the 52nd minute of Saturday's 2-0 victory and was forced to leave the pitch shortly afterwards.

The setback came after Konstantelias had made an immediate impact on his first league appearance for Dortmund, scoring his maiden goal for the club in first-half stoppage time.

Dortmund sporting chief Lars Ricken said the injury was a major blow after the new signing's promising start at the club. "This news hits us very hard because Giannis has already shown in a very short time why we see him as a great player for Borussia Dortmund," Ricken said. "For now, however, his focus and ours must be on his recovery. Giannis has our full support."

The injury leaves Dortmund assessing its options with the German transfer window due to close on Tuesday. Coach Niko Kovac had already indicated after the Hamburg match that the club would consider whether to respond in the transfer market, although he stopped short of saying another signing was certain. "We have to give it some thought," Kovac said. "We must look at what might still be possible. We don't know whether we will do anything. But at least we will consider it. That much is clear."

Konstantelias' absence represents an early setback for Dortmund after the Greek midfielder had marked his Bundesliga bow with a goal before his afternoon was cut short by the injury.

The club did not provide a more precise timetable for his return beyond saying he would be unavailable for several months. Dortmund said its immediate priority was now to support Konstantelias throughout his rehabilitation and recovery from the serious knee injury.