After a bright start to his Arsenal career, goals had dried up for the France international and late on in Saturday’s north London derby, he missed a gilt-edged chance to equalise when through one-on-one.
The 26-year-old was expected to start in the Europa League against Ostersunds on Thursday but he is now set for a spell on the sidelines.
Arsenal said in a statement: “Striker Alex Lacazette had an arthroscopy on his left knee in London on Tuesday morning.
“The minor procedure was a success and he will now undergo a period of rehabilitation.
“It is envisaged that he will return to the squad within four to six weeks.”
Lacazette could miss up to nine games including the doubleheader against Ostersunds, the Carabao Cup final against Manchester City and league games against Brighton, Watford and Leicester.
Following the arrival of Pierre-Emerick Aubameyang in January, Lacazette has started the last two games from the bench and Arsenal boss Arsene Wenger said he felt his goal drought could be down to the increased competition.
Wenger said: “For him, one against one with the keeper, he is a good goalscorer.
“He has gone through difficult periods before. He works hard in training, works on his finishing.
“I don’t know what happened, did he not touch the ball well? It can happen, it is a fraction of a second.
“Maybe the confidence is not at its highest because he has seen a competitor coming in for him.”