Arsenal captain Cesc Fabregas was ruled out of for one or two games after picking up a hamstring injury in Wednesday's match, confirmed the Gunners' boss Arsene Wenger on Friday.
The 23-year-old playmaker hobbled off after only 14 minutes with a hamstring problem on Wednesday but his teammates made sure to take a 1-0 victory over Stoke City at Emirates.
In Thursday evening, Wenger revealed that Fabregas would miss the League Cup final at Wembley on Sunday but didn't know how long the Spaniard would need for recovery.
On Friday, Wenger reiterated the absence of Fabregas and indicated a time scale for the midfielder's return
"He is injured and is out. We had a scan yesterday. He is out for one or two games, maybe," said the Frenchman.
England winger Theo Walcott will also miss the match on Sunday against Birmingham as he sprained his ankle in Wednesday's Premier League game.
"What is important now is that the team and the squad focuses on the game we want to play on Sunday. Ideally you want everybody fit but before the season starts you know you can have some players injured. We can deal with that," said Wenger.
The north Londoners are expecting their first trophy since winning the FA Cup in 2005.