Holding was taken off on a stretcher during the first-half of Arsenal’s 2-2 draw with Manchester United at Old Trafford on Wednesday, having broken into the first-team under Unai Emery this season.
The 23-year-old was taken back to London for tests following the collision with Marcus Rashford, with scans revealing he had ruptured the anterior cruciate ligament of his left knee.
“Rob will undergo surgery to repair this in the coming days,” the club said in a statement.
“The rehabilitation process is expected to take between six to nine months. “Everyone at the club will now be working as hard as we can to ensure Rob is back on the pitch as soon as possible.”
The long-term injury to Holding is the latest defensive setback for Arsenal, who remain without centre-back and captain Laurent Koscielny, as well as left-back Nacho Monreal.
“Just want to say a big thank you to all the fans, players and staff members for the support during the past couple of days,” Holding tweeted on Friday afternoon.
“Gutted to get injured during a strong period for the team!”