With Debuchy out for a while we'll have to play Callum Chambers at right back, leaving us no cover whatsoever at centre half.
Sagna and Vermaelen have both been sold, and Jenkinson is out on loan so there's a dearth of experienced replacements available.
This was always going to be a danger, and unfortunately it's happened sooner rather than later.
Will Wenger give one of our huge selection of midfielders a chance at right back? - you might laugh, but given his liking for playing people out of position this could well happen.
It's not good. We'll have to wait and see what happens. The extent of Debuchy's injury isn't known yet, and only the eternal optimists would predit a return inside a month.