Arsenal will be without midfielder Santi Cazorla for another three months after the club decided he should undergo ankle surgery.
The 31-year-old has already missed six weeks of action since suffering the injury in the Champions League match against Ludogorets on October 19.
After the problem did not heal as quickly as Arsenal had hoped, Cazorla will undergo surgery in Sweden next week in a bid to fully resolve the issue.
Arsenal's timeframe would mean Cazorla will not return to action until the start of March, for the closing stages of the 2016-17 season.
"The club's medical team and specialists have decided that surgery is required to the plantaris tendon in the Spain international's right foot," read Arsenal's statement on Thursday.
"The problem has not progressed during a rehabilitation programme following the injury.
"We expect Santi's full recovery to take approximately three months. Everyone at the club will be working hard with Santi to make sure he's back on the pitch as soon as possible."
The development comes as a major blow to manager Arsene Wenger, who stressed last week the club were missing Cazorla having won only one of their last five games across all competitions.
Per Mertesacker and Danny Welbeck are among Arsenal's other long-term injury absentees.