Arsenal manager Arsene Wenger says he is shocked after he was forced to replace three key players against Hull City.
The Gunners eased past Steve Bruce's side by 4-0 but defenders Per Mertesacker and Gabriel Paulista as well as midfielder Aaron Ramsey were all forced to abandon the game due to injury.
According to the Frenchman, the German defender suffered a concussion with Gabriel Paulista expected to recover in time to face Watford in the weekend.
But the 25-year-old Welshman could be sidelined for weeks with the Frenchman "a bit more concerned" with the fitness level of the midfielder.
"Mertesacker is just a cut on his eye and looks to be very short," Wenger said.
"Gabriel is a hamstring and Ramsey is a thigh problem. To me, the most serious looks to be Ramsey. He has a thigh problem, I think it is a thigh strain.
"We had a great game on Saturday and I was quite amazed by the response we got from that game.
"Overall, I believe that we do not always need confidence, you can play well when your confidence is not at the highest. Our job is to play and I believe that we have a great spirit in the team and we have shown that again tonight."