Gibbs (right) was injured in a hefty challenge from Standard's Eliaquim Mangala
Arsenal boss Arsene Wenger has confirmed that Kieran Gibbs has had surgery and faces three months out.
Gibbs, 20, injured his left foot in a challenge with Standard Liege's Eliaquim Mangala during the Gunners' 2-0 Champions League win on Tuesday.
"The first metatarsal is broken, which is very rare. He will be out for at least three months," Wenger explained.
With Gael Clichy also out, Armand Traore could deputise at left-back when Arsenal host Chelsea on Sunday.
However, with centre-back William Gallas also doubtful having hobbled off against Liege with an ankle injury, Wenger could start Mikael Silvestre, or even move either centre-back Thomas Vermaelen or right-back Bacary Sagna to the left.
Having seen first-choice Clichy ruled out for several weeks due to a back problem, Wenger was left fuming at the tackle that caused Gibbs' latest injury, the England-Under-21 international having only just recovered from an injury to his right foot.
"It was a very bad challenge by the number 22 [Mangala] and was not his first try," he said.
However, the Arsenal manager has conceded that even a first-choice defence would face a stern examination from Didier Drogba and former Gunner Nicolas Anelka in the league-leaders' attack.
"You know they are a good side and to beat them, you have to deliver a good performance," said Wenger.
"It is more important we focus on what we do than any strength or weakness of Chelsea.
"They are a strong side and have a good manager in Carlo Ancelotti, but I still believe that despite all that, we can still beat them.
"Let us expect them to be strong on the day, and then let us be stronger."
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