At one point or another since the beginning of 2014, Arsenal have had to deal with the absences of Aaron Ramsey, Theo Walcott, Jack Wilshere, Mesut Ozil, Abou Diaby, Laurent Koscielny, Tomas Rosicky, Nacho Monreal and Kieran Gibbs—often for very long stretches.
Perhaps some of the blame lies at Wenger's feet—due to poor squad rotation, for example—but Wenger has not had much opportunity to use his full and undoubtedly very talented squad. This has been one of Arsenal's most injury-plagued seasons in recent memory.
Whether that is down to bad luck, a shoddy medical staff or some combination of the two, the fact is that Arsenal are, and have been, severely depleted for almost the entire season. Surely that should not cost Wenger his job.