Borussia Dortmund midfielders Nuri Sahin and Sven Bender are set to miss Wednesday's must-win Champions League game at Marseille after picking up ankle injuries in Saturday's defeat to Bayer Leverkusen.
Germany's Bender was taken to hospital during Dortmund's 1-0 defeat at their Westfalenstadion, while his defensive midfielder partner Sahin soon followed in an ambulance after being helped off eight minutes from time.
Dortmund coach Jurgen Klopp said both players had been in severe pain and are extremely doubtful for Wednesday's match at Olympique Marseille, which Dortmund must win to reach the knock-out stages of the Champions League.
"Today is Saturday and while miracles do happen, they just haven't happened for us recently," said Klopp.
After losing his entire back four to injury last month before their 3-1 Champions League win at home to Napoli, Klopp has fresh woes with his side second in Group F behind Arsenal.
"This is not an easy phase for us," admitted Klopp.
"Given that two of our players are injured, possibly gravely so, it will make our next few games tricky."
Dortmund's fourth league defeat of the season leaves them third in the Bundesliga, seven points behind Leverkusen and 10 adrift of leaders Bayern Munich.