Hamburg centre back Michael Mancienne will be out for at least six weeks with torn ankle ligaments.
Mancienne, 25, had become a regular in Thorsten Fink's team after playing only 16 matches last season, and his injury has put Jeffrey Bruma's proposed loan move to the Netherlands on hold.
Former Chelsea player Mancienne, who had a spell on loan at Wolves, has established a solid defensive partnership with Heiko Westermann this season, with Thorsten Fink's side having conceded only 22 goals.
He suffered the injury at Nurnberg on Sunday, having to be substituted after only 14 minutes.
It means Bruma, on a two-year loan from Chelsea, may now not go on a further loan to the Dutch league, where he had been linked with both Eindhoven and Arnhem, Die Welt has reported.
Fink said: "I told him he will be important for us and get his chance to shine."
But Hamburg general director Frank Arnesen stressed that the club would still look to move one central defender on when Mancienne returned.
He added: "Michael's injury has changed nothing. He will be back, and we have five centre-backs in our squad - that's one too many."
Hamburg could now focus on offloading Slobodan Rajkovic, 23, while Arnesen is also trying to sell out-of-favour Gojko Kacar, Swedish striker Marcus Berg and Croatia international Ivo Ilicevic in his attempt to earn Hamburg €6.4 million in transfer fee and saved wages.