Arsenal manager Arsene Wenger fears he could be without Sol Campbell for up to three weeks after the defender injured his ankle in the 3-1 win at Charlton.
Campbell pulled up in pain after leaping to attack a corner and is set to miss the game against Manchester City at Highbury on Tuesday.
"It does not look too good. I think he will be a serious doubt for Tuesday night," said Wenger.
"His ankle has turned and usually that is a two-to-three-weeks job."
Two goals from Fredrik Ljungberg and another from Robin van Persie secured victory for Arsenal against a battling Charlton side who had been unbeaten in five Premiership games.
"It was a difficult game against a good team. Charlton are confident at the moment and they have good players," said Wenger.
"They came back to 1-1 just before half-time in a little bit of a controversial way, but then we scored straight away and 3-1 gave us a good cushion."
Wenger remonstrated with referee Mark Halsey at the interval over the free-kick which allowed Talal El Karkouri to equalise for Charlton.
"He gave it at a surprising moment when we had two against two on the other side of the field," said Wenger.
"Maybe he thought they would win the ball. Was it a foul or not, I don't know?
"They contested the second goal we scored because apparently Van Persie came back late from an offside position.
"I thought overall it was a good game. Charlton deserve a lot of credit. An average Arsenal side would not have won this game.
"It was very difficult for us and we needed some great performances to come home with the three points. Our experienced players have been amazing.
"We'll get as many points as we can and if we get to the last seven or eight games in this position I'll start to look at the results of the other teams."