Arsenal goalkeeper Arsene Wenger has confirmed that goalkeeper Petr Cech will be out of action for "three or four" weeks with a calf injury.
The 33-year-old pulled his hamstring during the Gunners' 2-1 defeat to Swansea City at the Emirates on Wednesday evening.
Not only will Cech be absent from this Saturday's North London derby against Tottenham Hotspur, he is also likely to miss Arsenal's FA Cup replay against Hull City, the last-16 second leg against Barcelona in the Champions League and a Premier League clash away to Everton.
Wenger, who has overseen his team lose their last three games in all competitions, confirmed the extent of Cech's injury in Friday's press conference.
The blow comes after Arsenal dropped points in the Premier League title race after suffering defeat to Manchester United and Swansea.
The Gunners, who will play David Ospina in Cech's absence, are third in the table, six points behind leaders Leicester City.