Arsenal will be going into this weekend's FA Cup match against Sunderland without their two most consistent central defenders from this year, according to Arsène Wenger today at his press conference. The bad news is that Per Mertesacker has had surgery on his ankle and is out for the long term, which sounds a little bit like a season-ender:

Unfortunately he has had surgery and we have lost him for a while. How long I don’t know. He had reconstruction of his ligaments. So it will be long term.

"Surgery", "reconstruction", "for a while", "long term"...this is a bummer, man. Mertesacker seemed to have settled into a groove and found ways to overcome his main weakness--pace--and establish himself as a solid option at center back, and a freak injury has put his season in jeopardy.

Laurent Koscielny, however, looks to have come through his knee problem in relatively good shape.

He had a scan yesterday and the news is quite good. He will be out for hopefully around a week. He will miss the Sunderland game. But he should be back for next week.

This is a relief, as he has been Arsenal's best defender this year by some distance. Losing him for a huge FA Cup match tomorrow will make that task very difficult combined with Mertesacker's absence, but Arsenal still have Thomas Vermaelen and Johan Djourou to call upon, and Alex Song can always fill in at the back in an emergency capacity, so it could be worse. Arsenal could be starting their 178th full back this year.