David Luiz faces a spell on the sidelines after undergoing a "small procedure" on his right knee.
The 33-year-old was absent from Arsenal's 3-0 defeat against Liverpool on Saturday with a knee problem but did play the full 90 minutes when the Gunners drew 3-3 with West Ham before the international break.
Arsenal confirmed Luiz will be unavailable in the "upcoming weeks" after undergoing surgery on Sunday morning.
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"The procedure has been a success and David is now back at home rehabilitating," an Arsenal statement said.
"He will be able to return to daily support and recovery with our medical team at the training centre in the coming days.
"David is expected to be back to full fitness and available for selection in the upcoming weeks."
Arsenal's preparations for Thursday's Europa League quarter-final first leg against Slavia Prague suffered a separate setback as Kieran Tierney was withdrawn before half-time against Liverpool with a knee problem.
Tierney is a doubt for that match and manager Mikel Arteta confirmed they do not yet know the severity of the injury.
Arteta said: "He felt something in his knee and he was in pain so it looks like he will be injured, but we don't know for how long."
Arteta apologised for Arsenal's insipid performance against Liverpool, admitting his players should have lost by a bigger margin.
Liverpool were back to their scintillating best at the Emirates Stadium as they dominated Arsenal and secured a 3-0 win courtesy of two goals from substitute Diogo Jota either side of a Mohamed Salah strike.
Arteta told Sky Sports: "We completely deserved to lose the game. They were better in every department and deserved to win the game with the margin they had, or even more. I accept responsibility for the way we played today.
"At the moment I am in shock. I didn't expect that because of the way the team trained."