Arsenal face selection difficulties ahead of Champions League tie

Abou Diaby will miss tomorrow's Champions League clash with Olympiakos, and the next three weeks, with a thigh strain.

The France international picked up the injury in Saturday's 2-1 defeat to Chelsea and could be joined on the sidelines by Mikel Arteta, who faces a fitness test on an ankle knock tomorrow.

Jack Wilshere (ankle) sharpened his fitness with an Under-21s game and Wojciech Szczesny (ankle) faces a further three weeks out. Bacary Sagna (broken leg) trained today but is unlikely to feature.

Arsenal provisional squad: Mannone, Gibbs, Mertesacker, Vermaelen, Jenkinson, Cazorla, Arteta, Gervinho, Podolski, Giroud, Martinez, Walcott, Coquelin, Santos, Djourou, Oxlade-Chamberlain, Ramsey, Koscielny, Arshavin, Gnabry.