Santi Cazorla has been ruled out for three months through injury.
The midfielder continued to play during the weekend’s game with Norwich, despite suffering a knee injury.
Alexis Sanchez also picked up a hamstring problem during the game.
The Spaniard is now set for a three month spell on the sidelines after concerns about damage to his knee ligaments.
Arsenal are now quite light in midfield, with Frnacis Coquelin, Jack Wilshere and Tomas Rosicky already out.