To be fair, if the Richardson story is true then who else can Wenger go for? We need someone to come in on a short-term basis and instantly do a job, so you're looking at current Prem players. No-one in the top 6 is going to give us anyone that isn't Bridge and no-one else is going to give us their first-choice LB. Who else is out there that is half-decent and at a club with a big enough squad to be able to allow them to leave? I can't think of anyone realistic that isn't a inexperienced youngster and if we go down that route we might as well play our own.
He'll get attacked if he doesn't bring anyone in, but we have plenty of defenders, just a freak concentrated injury crisis. There's no point getting anyone on anything but a short-term loan to see out the period until our fullbacks come back, unless it is a LB/LW like Vargas who can add to the squad other than being a stop-gap. Even then, by the time they adapted to the league/team our regulars would probably be back, so would we be any better off from the millions spent on a transfer fee/wages across a few years of contract?