The defender picked up the injury in Arsenal's 2-1 Premier League defeat to Chelsea on Sunday and has now undergone surgery which will rule him out of the rest of the 2019-20 season:
"Calum has had successful surgery in London on Thursday morning. The rehabilitation process is expected to take between six to nine months. Everyone at the club will be supporting Calum to ensure he is back on the pitch as soon as possible."
The injury is a blow to the Gunners as Chambers has been in good form for the club this season and had been one of the club's strongest performers in a disappointing campaign:
Arsenal also confirmed Chambers will be joined on the sidelines by left-back Kieran Tierney. The Scot is out for three months after undergoing surgery on a dislocated right shoulder.
The injuries mean Arsenal are short of options in defence and could look to bring in reinforcements during the January transfer window.
Manager Mikel Arteta told reporters on Thursday that Chambers' injury may impact their transfer plans, but he does not seem to be expecting a busy window, per James Olley at the Evening Standard:
James Olley @JamesOlley
Arteta on Chambers injury & transfers: "That's obviously going to change our plans at the back but the reality at the moment is we are not going to be able to do much. I’m more concerned to get people back from injuries than signings & try to improve the players that I have."
The Gunners are also considering recalling William Saliba from a loan spell with Saint-Etienne, per Liam Prenderville at the Mirror. Arsenal signed Saliba in the summer from the Ligue 1 side but agreed to loan him back for 2019-20.