Arsenal have confirmed that Jurrien Timber suffered an anterior cruciate ligament injury to his right knee and will undergo surgery.
The 22-year-old limped off the pitch in the 50th minute of the Gunners’ 2-1 victory against Nottingham Forest on Saturday.
Timber signed from Ajax for £34m in July, and prior to his injury was becoming fans’ favourite with his impressive displays.
In a statement, Arsenal said Timber “will be out of action for a period of time” without specifying a duration.
The club added: “The support and expertise from our medical team and everyone at the club will now be focussed on Jurrien’s rehabilitation programme, to ensure he recovers well and is back playing as soon as possible.”
Timber debuted for the Gunners in the Community Shield victory against Manchester City before featuring in the season opener with Forest.
Mikel Arteta, however, had to bring on Takehiro Tomiyasu in the second half after the Dutchman communicated with the bench that he could not continue.