We're stacked in midfield where Nasri can do a job, he is not a left sided defender where we are short. Nor is he primarily a goal scorer / forward where Pep apparently wants to strengthen.I mean, whoever we intend to bring in, Nasri can do there job. Maybe not as well. But he can. And if its a backup we seek, why not Nasri?
He would be a back up in an area where we are already strong and probably get frustrated.