Santi Cazorla has undergone knee surgery in Spain and Arsenal are reportedly concerned that the playmaker could miss the rest of the 2015-16 season.
The 30-year-old flew back to his homeland for surgery at the weekend after rupturing his lateral ligament.
Manager Arsene Wenger initially ruled him out for three months, but according to The Mirror, the Frenchman does not expect Cazorla to play again this season.
He is the latest blow in a worsening injury crisis which has seen Alexis Sanchez and Francis Coquelin both ruled out until the new year recently.
The Gunners sit second in the Premier League table, two points behind leaders Leicester City.
