Arsene Wenger says Arsenal midfielder Francis Coquelin will be out for 12 weeks with a knee ligament injury.
But Wenger has stated the injury, which Coquelin suffered during the Gunners' 2-1 defeat at West Brom on Saturday, does not require surgery.
Coquelin had a scan on the problem on Monday, after which Wenger said the French midfielder would be on the sidelines for at least two months.
And the Arsenal manager has now put an even more conservative time-frame on his return, with Coquelin not expected back until the middle of February.
"It is what we feared," he said following Arsenal's 3-0 win over Dinamo Zagreb in the Champions League. "Let's be realistic - it will be 10 or 12 weeks.
"He doesn't need surgery but it will be a minimum of 12 weeks."
Wenger did however say that Theo Walcott and Alex Oxlade-Chamberlain will be available for available for Arsenal's final Champions League game, against Olympiakos in Athens on December 9.