Leyton Orient v Arsenal preview

Leyton Orient midfielder Matthew Spring is doubtful for the visit of the Gunners.
Spring has missed the last two matches with a calf problem and will be handed a late fitness check.
Fellow midfielder Adam Chambers is a definite absentee with a shin injury which is expected to keep him out for another fortnight, but boss Russell Slade has an otherwise fully-fit squad to choose from.
Defender Terrell Forbes will hope for a recall after dropping to the bench at MK Dons in midweek, while striker Jonathan Tehoue is pushing to start after climbing off the bench to hit the winner.
Orient head into the tie in fine form, having lost just once in their last 20 matches and on the back of three straight wins which have lifted them to within three points of the play-off places.
Theo Walcott is expected to recover from a slight hamstring strain for the FA Cup tie at Leyton Orient.
And centre back Johan Djourou is also likely to be included in the squad if he recovers from a back problem he suffered against Barcelona in midweek.
Right-back Bacary Sagna is available after returning from suspension but midfielder Abou Diaby is still banned.
Striker Marouane Chamakh will return to the squad after missing out against Barcelona.
Arsenal (from): Szczesny, Eboue, Koscielny, Clichy, Song, Djourou, Arshavin, Wilshere, Walcott, Bendtner, Chamakh, Fabregas, Nasri, van Persie, Almunia, Rosicky, Sagna, Denilson, Squillaci, Gibbs.