Arsenal boss Arsene Wenger is facing a defensive injury crisis after the club confirmed Andre Santos will be out of action for months.
The Brazilian international moved to the Emirates from Fenerbache for a reported £6.2 million in the summer, and quickly became a regular following injuries to his rival teammates in the position.
However, the 28-year-old is the latest Gunner to be ruled out after damaging ligaments in his ankle against Olympiacos in the Champions League, with a prolonged period on the sidelines expected.
"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 sustained in the game against Olympiakos last week," read a statement on the official website.
"Andre will have surgery in Brazil this week and is expected to be out for around three months.
"Everyone at the club wishes him well."
Santos joins Bacary Sagna (broken leg), Carl Jenkinson (back stress fracture) and Kieran Gibbs (hernia) on the treatment table at the Emirates Stadium, leaving many to predict the Frenchman will turn to the transfer market when it re-opens in January.
Laurent Koscielny has so far impressed in the right-back position in north London, whilst Johan Djourou was used as the other full-back on Saturday in the 1-0 win over Everton.
The pair are set to continue out-of-position for the immediate future, although the busy festive period could stretch Arsenal to their limits with a trip to Manchester City on Sunday looming large.