The England international has been sick and therefore was not present at The Emirates.
Arsenal defeated their 'bogey team' Stoke City today in comfortable fashion at The Emirates, a 3-0 win courtesy of some excellent football from £35 million summer signing Alexis Sanchez.
It was also a game in which Arsene Wenger would have been pleased to welcome back two of his star players from injury.
Mesut Ozil came on after several months out with knee ligament damage and Aaron Ramsey was also back on the bench, although his best was saved for the Manchester City game next week.
But they also suffered an injury in the game. Mathieu Debuchy, who had already had a long spell out of the team this season, was shoved into the advertising boardings by an apologetic Marko Arnautovic - and dislocated his shoulder.
It was a sickening injury but Arsenal have plenty of cover at right-back, but not today. Young Spaniard Hector Bellerin came into the fray as summer signing from Southampton Calum Chambers was absent.
So why was Chambers not present and should Arsenal fans be worried about who will replace Debuchy, for what will certainly be a lengthy absence?
No. Wenger confirmed the reason why Chambers was absent after the game, in quotes published by Arsenal.com, and it is certainly not serious:
"Chambers was sick. I took him with the team but I decided at the last minute to leave him out of the squad because he’s been sick in the last two days."
Chambers better get well soon, because with Debuchy now out of action he is needed in the Arsenal defence.