Free agent, cheap (so doesn't impact the fair play wage limit) and although he hasn't played for a while, he can get match fit pretty quick. (claretandhugh.info)
When he's fully match fit he does get back and help his full back. (justarsenal.com)
I'm sure you yourself could imagine — player out for one whole season and not even match fit / transfer window just gone.. (justarsenal.com)