Arsenal have confirmed that striker Alexandre Lacazette will be out of action for up to six weeks with a knee injury.
The 26-year-old forward underwent surgery on Tuesday and is now expected to be out of action for at least a month as he recovers.
A statement on the club's official website read: "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 initially impressed following his £46 million move from Lyon in the summer, scoring eight goals up to the beginning of December.
He has, however, struggled to find the back of the net since then, with just one strike coming in the 4-1 win over Crystal Palace on January 20.
And the Frenchman was further criticised following his brief cameo in the north London derby defeat to Tottenham, with Lacazette missing the target with two presentable chances towards the end of the game.
That led manager Arsene Wenger into suggesting that the forward may have had his confidence knocked since the club-record arrival of Pierre-Emerick Aubameyang from Dortmund.
He said: "For him, one against one with the goalkeeper, 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 [with his second miss against Spurs], 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."