Per Mertesacker was stretchered off during Arsenal's 2-1 League win at Sunderland
An ankle ligament injury will rule Arsenal defender Per Mertesacker out for the "long term", Gunners boss Arsene Wenger has said.
The Germany international was injured during Saturday's 2-1 Barclays Premier League victory at Sunderland and had to be carried off.
Mertesacker did not feature in the midweek Champions League defeat at AC Milan.
"He had reconstruction of his ligaments, so it will be long term"
- Arsene Wenger
On Friday, Wenger told the club's official website: "Unfortunately he has had surgery and we have lost him for a while.
"How long I don't know. He had reconstruction of his ligaments, so it will be long term."
The news will cast a shadow over Arsenal's run-in to the League season and could have hit Mertesacker's chances of playing for Germany in Euro 2012 in the summer.
Elsewhere there was better news for the Gunners as Wenger said the knee injury picked up by Laurent Koscielny against Milan was only likely to rule the Frenchman out for one week.
"He had a scan [on Thursday] and the news is quite good," said Wenger.
"He will be out for hopefully around a week. He will miss the FA Cup tie against Sunderland, but he should be back for next week."
Gervinho is also back after international duty with Ivory Coast at the Africa Cup of Nations, while Kieran Gibbs suffered no setback after playing his first match in four months in Milan.
