Arsenal manager Arsene Wenger has revealed Mikel Arteta will be sidelined for around three weeks with a calf injury.
Arteta, 30, had played every minute of Arsenal's Premier League matches this season until he missed Sunday's 2-0 loss to Manchester City.
The Spaniard will now out for three weeks, meaning he will be absent for the FA Cup third round replay with Swansea, and Premier League games versus Chelsea, West Ham and Liverpool.
Wenger said at his press conference: "He has a scan on Monday. He will be out for approximately three weeks. It is a calf strain.''
Abou Diaby made his return to the Arsenal side in Arteta's absence, playing 61 minutes having been injured since September.