Shkodran Mustafi will miss the busy Christmas period after Arsenal manager Arsene Wenger confirmed the defender will be out for at least three weeks with a hamstring strain.
Mustafi suffered the setback in Saturday's 3-1 win at home to Stoke City, which sent his side to the top of the Premier League, but he will be unavailable for upcoming games against Everton, Manchester City and West Brom.
Wenger insisted the German was not carrying an injury from the Champions League trip to Basel in midweek and the centre-back had declared he was fit to play.
"It's a bad one," said Wenger. "He had nothing in midweek, [if he had] I would not have played him today.
"I had Hector Bellerin on the bench. I could have played [Rob] Holding or Gabriel. He wanted to play in Basel, because he said, 'no it’s nothing' and it was completely clear.
"I checked three times and there was no problem. I don't know why it happened, but it looks a 'good' hamstring strain.
"The minimum when you go out like that is 21 days. After that, today is December 10, so you are 21 days, that means he'll have a nice Christmas!"
Despite losing Mustafi to injury, Wenger said he was happy with the depth to his squad, with Alex Iwobi coming on as a substitute to score Arsenal's third goal that wrapped up the victory.
"I have top quality on the bench – there’s not one player you can question," added he Frenchman. "I must say it's typical in the Premier League.
"When you look at the teams we play against, even the mid-table teams, when you look at their bench, there's top quality on the bench.
"They had [Peter] Crouch coming on, who nearly punished us. It could have been the 2-2 on a header."
The result was the Gunners' 15th consecutive home win over Stoke in all competitions.
