The Blues confirmed on Friday that Walsh has undergone a micro-discectomy procedure to aid his rehabilitation ahead of the new year.
“Throughout the last few months our number one priority has been for Sam's wellbeing in managing this issue, which is why we explored every possible conservative treatment option," Carlton football boss Brad Lloyd said in a club statement.
“Following this extensive process, it was clear that given all alternative treatments had not progressed his recovery, surgery was the required option to correct the issue.
“Sam is now recovering after undergoing surgery last night and will commence his rehabilitation in the New Year.
“While Sam's professionalism and resilience is well-known, we will absolutely give Sam all the time he needs to make a full recovery before he returns to the side during the season.
“Due to the long-term nature of this rehabilitation, it isn't possible to confirm a set date for his return right now. Once the opening month of the season has been completed though, we expect to be able to provide more clarity on his expected return to play.”
Walsh missed the Blues' final match of the home and away season as a late withdrawal with the back issue, however the same ailment looks set to see the young midfielder miss the start of next season following the operation.
The news comes after Carlton detailed they have looked to address their concerning injury trends from this year.
Carlton's 2023 campaign will begin on March 16 at the MCG against Richmond.