Wojciech Szczesny is out with a rib injury. With Per Mertesacker and Carl Jenkinson filling in for Laurent Koscielny and Bacary Sagna, this means more pressure on the back four to step up. Add Abou Diaby making his second Premiership appearance after a long, long injury absence and this could be a very long afternoon for the Gunners on set pieces and counterattacks.