He'll be around, don't worry.
Arsenal have many problems going into the season opener on Saturday, no doubt. The biggest one is depth, but at what positions is a question that is up for a good deal of debate. Central defense is one position that most supporters and media pundits see as the biggest problem, while for others it's left back, defensive midfield cover, striker, or right back. Center half depth reads, at the moment: Thomas Vermaelen, Laurent Koscielny, Johan Djourou, Sebastien Squillaci, Ignasi Miquel. Most supporters don't want to see Squillaci on the pitch, really, but injuries and fixture congestion mean that he will undoubtedly see time this year. This has led to a great deal of speculation in the media and Arsenal world about who MUST come in to the central defense: Phil Jagielka, Christopher Samba, Gary Cahill, Per Mertesacker...
Well, Raphael Honigstein, who is generally one of the best football journalists on earth, put this out on twitter a bit earlier today:
Wenger in Kicker today: no interest in Mertesacker. "We have four central defenders, no need for another one" #AFC
That seems pretty decisive, and perfectly Wengerian.
Right; who wants a left back, then?
UPDATE: lots of people on twitter saying it could be an old quote (Wenger does have his store of go-to phrases, after all), but even if it were, you know, would you really be surprised if he rolls with the four CBs he has at the moment?