The club’s record signing scored his seventh goal of the season with less than three minutes on the clock against Huddersfield on Wednesday.
Arsene Wenger‘s side would go on to thump the Terriers 5-0 with a second half onslaught at the Emirates for a 12th consecutive home win.
But a huge dampener was put on the night when the French striker was forced off at half time.
And his boss confirmed it was bad news for Lacazette after the clash.
Wenger said: “It is an injury, it looked like a groin injury so he might be out for a while.”
He later confirmed: “Lacazette has a groin problem and he will certainly be out for Saturday’s game.”