London-based French journalist Julien Laurens reports that he's spoken with defender Laurent Koscielny, who says that the knee problem that kept him out of today's 3-0 win against Aston Villa is not serious, and he should be able to be in the team next weekend when the team faces Queens Park Rangers.
Koscielny suffered the injury, described as a "flare-up," in the warm-up before today's match, and had to be replaced at the last minute by Johan Djourou. The Swiss defender had a good game against the Villans, and was superb much of last season as a replacement for Thomas Vermaelen as he missed most of the season. However, after suffering a shoulder injury in an FA Cup loss to Manchester United, Djourou lost form and hasn't really found it since.
Additionally, Koscielny has been one of the best defenders in the league this season (if not the world) and has been one of Arsenal's most valuable players, so a long-term injury would be very bad news. This, if Koscielny is not mistaken, is precisely the opposite of bad news.
Here is the actual tweet from Laurens:
UPDATE: According to Jamie Sanderson, Arsenal manager Arsene Wenger implied in his post-game press conference that Koscielny may have just slept on his leg awkwardly, and confirmed that he should be fit for QPR.