Giroud, 27, suffered the injury in the Gunners' 2-2 draw at Everton on Saturday, shortly after ensuring a share of the points by scoring Arsenal's 90th-minute equaliser at Goodison Park.
He needed an extra scan to reveal the full extent of the damage once swelling in the injury, which hampered initial investigations, had gone down.
If Giroud is ruled out, Arsenal manager Arsene Wenger can still turn to Alexis Sanchez, Joel Campbell, Yaya Sanogo and Lukas Podolski as attacking options.
However, Sanogo has recently been out of action sidelined with a hamstring problem and looks certain to miss Wednesday's Champions League qualifying second leg against Besiktas.
Source : AFP
Source: AFP