The Champions League runners-up lost another two players to injury on Saturday, leaving Jurgen Klopp bewildered by the continued misfortunes.
Both players were forced off during the game and though the severity of the injuries are not yet fully known, early indications have suggested that Bender will definitely miss the crucial Champions League clash with Marseille on Wednesday night, while Sahin is rated at just 50/50 to start the game.
The pair joins Mats Hummels, Neven Subotic, Ilkay Gundogan and Marcel Schmelzer on the sidelines as injuries threaten to seriously undermine BVB's season.
"We lost 1-0, but that's the least of our problems today," coach Jurgen Klopp told reporters after the defeat.
Dortmund's depleted squad travels to Marseille on Wednesday night in its final Champions league game of the group stage, with the Signal Iduna Park club needing a win to stand any chance of progressing to the knockout stages.