Schalke 04's Christoph Metzelder, Mario Gavranovic and Peer Kluge are doubtful for their Champions League quarter-final first leg at holders Inter Milan next week after being injured against St Pauli on Friday.
Central defender Metzelder broke his nose and could potentially play with a face mask, but 21-year-old forward Gavranovic's ankle injury looked more serious, coach Ralf Rangnick said on Saturday.
Midfielder Kluge picked up an abdmominal muscle injury in the game at St Pauli, which was abandoned after a linesman was hit by a beer cup.
"Christoph could maybe play with a mask," Rangnick said, adding that Swiss international Gavranovic would undergo further tests at the weekend to determine the extent of the damage.
Schalke, who are 10th in the Bundesliga and qualified for the German Cup final before Rangnick replaced Felix Magath two weeks ago, travel to Inter on April 5 before hosting the Italians on April 13 in Gelsenkirchen.