Arsenal defender Andre Santos will undergo ankle surgery this week and is expected to be sidelined for around three months, the Premier League club said on Monday.
The Brazil international, who joined Arsenal from Fenerbahce in August, suffered ligament damage in their 3-1 Champions League defeat to Olympiakos Piraeus last week.
"Arsenal Football Club can confirm that, following investigations and subsequent medical opinions by club specialists, left-back Andre Santos will have surgery to repair ligament damage in his right ankle," the club said in a statement on their website.
The injury is a further headache for manager Arsene Wenger who is currently without defenders Kieran Gibbs, Bacary Sagna and Carl Jenkinson.