Arsenal midfielder Tomas Rosicky is likely to be out for a month with a groin injury, with Arsene Wenger 'devastated' by the news.
Rosicky was replaced by Carlos Vela at half-time in Saturday's 2-0 win over Stoke City and is now set for another spell on the sidelines.
The Czech Republic ace only returned from more than 18 months out of action in September and had been looking to recapture his best form.
He could now be missing from the Gunners' plans until the New Year, leaving manager Wenger counting the cost of another injury.
"He's devastated and I am as well," Wenger said.
"Before the (Stoke) match I told myself 'he has played the whole game on Wednesday, should I take the gamble or not as it was such an important game?'. But by half-time he was struggling."
Wenger also had to do without Eduardo for 18 months after he broke his leg against Birmingham in 2008 and believes Rosicky is encountering the same issues as the Croatia striker.
He added: "It's a vicious circle when you have been out for a long time. Eduardo had not played for 18 months, Tomas has not played for 18 months.
"When you come back, one or two games, your body has to get used to producing the energy levels again and it's difficult. Nobody masters that.
"The first impression for me is that it won't be longer than a month, but it's a groin problem so we have to see the scan in 48 hours which grade it is - grade one is 10 days but grade three is three."
A further four players picked up knocks against Stoke, while Wenger is also missing several key players due to injury.
"We pick up more injuries than the other big teams, that is true," Wenger said.
"You cannot say there is not a reason for it, but we have not found it yet.
"It's the worst season for injuries for us. And they are all in the same area - in the offensive side. Last year it was in the defensive side."