Arsene Wenger expects Wojciech Szczesny to be sidelined for around six weeks with a finger injury, and admits Arsenal "absolutely need some cover in goal".
The 20-year-old Pole - who started the season as the Gunners' third choice - suffered a dislocated finger in Tuesday night's Champions League defeat to Barcelona at the Nou Camp when he was hurt saving Dani Alves' 16th-minute free-kick.
Wenger told Arsenal TV Online: "We have Wojciech out - in my opinion for six weeks. We have (Lukasz) Fabianski out for the rest of the season. We absolutely need some cover in goal."
Former number one Manuel Almunia, 33, came on to make some eye-catching saves as the Catalan side ran out 3-1 winners to end Arsenal's European hopes for another season.
However, with Fabianski already ruled out for the rest of the season after shoulder surgery and Vito Mannone troubled by a thigh injury while on loan at Hull, Wenger looks set to ask the Barclays Premier League for permission to bring in experienced cover, with youngsters James Shea, 19, and Damian Martinez, 18, the only other fit keepers.
"We need now an experienced goalkeeper as cover for Almunia because Mannone is out for six weeks so we cannot call on him," Wenger added.
"Mannone is here at the training ground having treatment, but he cannot play for the next six weeks. We can call him back (from Hull), but he is not available."
Almunia had looked set to leave Arsenal during the January transfer window, but the Spaniard now finds himself thrust back into the first-team picture ahead of Saturday's FA Cup quarter-final at Manchester United.
Wenger has been impressed with Almunia's approach to the situation.
"He is very professional, (has a) very dignified attitude and overall he has done very well," the Arsenal boss said. "Yes, he has done quite well when he came on (against Barcelona) and was quite busy in the final part of the game and he did very well."