The 28-year-old France centre-back was hurt trying, in vain, to prevent City's second goal, scored by Alvaro Negredo five minutes before half-time in the lunchtime kick-off at the Etihad Stadium.
After receiving treatment on the pitch he was taken off and replaced by Thomas Vermaelen, with Arsenal swiftly confirming on Twitter: "The injury to Laurent Koscielny is a deep laceration. #MCFCvAFC."
Source: PA
Source: PA