Arsene Wenger said he was in shock after losing three more key players to injuries in Arsenal's FA Cup win over Hull, with Aaron Ramsey the biggest concern after sustaining a thigh problem.
Arsenal cruised into the quarterfinals with a 4-0 win at the KC Stadium on Tuesday but the victory was costly as centre-back pairing Per Mertesacker and Gabriel Paulista both had to come off injured.
Ramsey was brought on as a substitute but then had to exit himself after just 15 minutes on the pitch.
"I'm a bit under shock there because we lost our two centre-backs in the game and after we lost Aaron Ramsey," Wenger told BT Sport.
"Mertesacker is just a cut on his eye and looks to be very short," he later told a news conference. "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."
Laurent Koscielny is already sidelined with a calf problem, but Wenger had previously said he expects the defender to be back for this weekend when Arsenal face Watford in their next FA Cup game on Sunday.
Barcelona then await next Wednesday in the return leg of their Champions League last-16 tie, and Wenger will be hoping that both Mertesacker and Gabriel will have recovered by then.
Mertesacker clashed heads with Nick Powell in the first half and stayed down for treatment for several minutes. He tried to play on despite a swollen left eye but eventually asked to be substituted.
Gabriel then limped off early in the second half. Wenger had only included one defender on the bench in Nacho Monreal, who came on for Mertesacker to deputise at centre-back.
When Gabriel went off, Calum Chambers had to move into the middle and midfielder Mathieu Flamini played as a right-back. It didn't matter, though, as Olivier Giroud and Theo Walcott scored two goals apiece to end Hull's resistance following a 0-0 draw at the Emirates.
But even Walcott was muted in his celebration after the game given the growing list of players in the Arsenal treatment room, saying: "The only disappointing thing when you look back at this game is the injuries we've picked up."
Cup holders Arsenal must now face Watford and Tuesday's replay success puts Wenger's men on course to win it for a third successive year.
''Look, do you know someone who has won it more than me? No, so that gives you the answer,'' the Frenchman said when asked what a third straight FA Cup would mean.
''We judge the season after the season and I'm quite amazed so many people judge it so early, you know.
''Assess the season after the season and we'll give everything. We have not given up anywhere and you will see that in the coming weeks. I believe that this club has been in a much worse position than it is today.''