The England international looked in discomfort after going into a challenge with Gaston Ramirez.
Not the best day at the office for Arsenal as they could only manage a 2-2 draw against Hull City in what was, in all fairness, a rather tepid display from them.
An early goal from Alexis Sanchez should have been the lick off to a comfortable victory - however, goals from Momo Diame and Abel Hernandez saw Hull lead for the majority of the game.
It was not until Danny Welbeck, a player Arsenal beat Hull to the signing of, scored in the 90th minute that Arsenal were back level.
But it was not just the dropping of two points that went wrong for Arsenal today.
Just as injury problems seemed to be easing, with Theo Walcott and Serge Gnabry returning to action last night and Aaron Ramsey making a surprise appearance today, Jack Wilshere looks to have suffered a nasty knee injury.
It is currently being described as a 'twisted knee' - but the game with Anderlecht already looks like a no go for the in form England international.
With Mesut Ozil, Olivier Giroud, Mathieu Debuchy and Laurent Koscielny also out injured Arsenal will hope it is not too serious.