Arsenal's Per Mertesacker: Unused sub in return from injury

Mertesacker (knee) was an unused substitute for Saturday's FA Cup match against Southampton.

Analysis:

Mertesacker made the bench for the first time this season after suffering a serious knee injury back in July, and while his availability is a boost to the Gunners' depth, he's unlikely to get much playing time in Premier League matches while Laurent Koscielny and Shkodran Mustafi are fit.