As both Arteta and Wilshere are unavailable, Wenger might revert back to the system he used at the start of the season. In that system, Song was a lone anchor man in a 1-2 midfield setup. However, in recent months the system has been tweaked to be more similar to the system played last season – featuring a traditional #10 role occupied by Ramsey.
We’ll have to wait until the game starts to learn about the positioning of Walcott and Chamberlain. They will surely switch flanks, but Chamberlain is more comfortable on the right.