Arsenal's manager, Arsène Wenger, confirmed the goalkeeper would be out for 4 weeks
Arsenal lost one of their best players before the Champion's League last 16 round second leg against Baràa. Petr Cech will be out for 4 weekd because of a muscle injury.
Arsenal's manager explained it himself in the press conference and, in addition, announced that the goalkeeper played with muscular pain in the adductor against Swansea, that bothered him when hitting the ball.
In those circumstances, the Colombian international goalkeeper, David Ospina, will be in charge of keeping Arsenal's goal clean in the next games. First against Tottenham and West Bromwich in Premier League and then at the Camp Nou against Barça, that has a 2-0 lead from the first leg.
During the same press conference, Wenger confirmed Laurent Koscielny still hasn't recovered to play this weekend but that he could be available against Barça. However, Wilshere is still out and won't be able either to play at Camp Nou.