Koscielny out 3 weeks; Arteta and Flamini also to miss United visit

Arsenal boss Arsene Wenger has confirmed that Laurent Koscielny could be out for three weeks with a hamstring strain, while Mikel Arteta and Mathieu Flamini will be absent for Sunday's visit from rival Manchester United.

The French defender was substituted in the 57th minute of the Gunners disappointing 3-2 home reverse against Olympiacos in the Champions League.

After United's visit and the international break, the North London outfit makes the short trip to Watford on Oct. 17. Following that is a pivotal Champions League game against Bayern Munich at the Emirates Stadium, and although Oct. 20 is within Wenger's predicted three-week timeline, it's expected they'll try to rush him back for the German champion's visit.

Thankfully for Wenger's side, Gabriel Paulista's reduced ban means he can return to compete for a centre-back partnership with either Per Mertesacker or Calum Chambers.

Francis Coquelin is also expected to be available following his substitution after an hour of the Olympiacos match with a knee issue.