Michael Zorc and Jurgen Klopp are far from pleased with the defender being out for the season, while Marco Reus has revealed his disappointment at results
The Serbia centre-back was ruled out for six months after tearing his cruciate ligament in Saturday's 2-1 defeat to Wolfsburg.
BVB chief executive Zorc told Bild "it's a really sh***y day" upon hearing that his club would be without the first-team defender for the remainder of 2013-14, while coach Jurgen Klopp admitted "it is terrible news".
Dortmund have now lost successive games - at home to Arsenal and away to Wolfsburg - and they are at risk of going out of the Champions League and falling behind Bayern Munich in the Bundesliga.
"We have lost two important games in a row," Reus said. "That's not good."
Dortmund's next two games could have a massive impact on the outcome of their season - first up is a home clash against Bayern Munich before a must-win European clash with Napoli.
BVB now trail the Bavarians by four points in the Bundesliga, with Pep Guardiola's men running out 3-0 winners over Augsburg on Saturday.