Walsh missed his side's Round 23 clash with Collingwood due to the ailment, with his 20-game campaign bookended by injury.
The All-Australian midfielder was a late out for Carlton's final game of the season, a match where the Blues required a victory to clinch a top-eight spot.
The Magpies would secure a one-point win over their Victorian rivals to spell an end to their year, forcing Michael Voss' side back to the drawing board.
As the Blues prepare for their second season under Voss, continuing the early stages of their pre-season training, Walsh remains sidelined from skill drills and full training at Princes Park as he manages the back issue.
Walsh is expected to remain away from the main group until the new year, with his setback unlikely to see him miss the opening round of next season.
Walsh missed his side's season opener against Richmond this year due to an ankle injury sustained at training. He was initially expected to miss the first month of the home and away season due to the syndesmosis setback, however made a return in Round 2.
In the chance Walsh is sidelined early into the new season, the Blues will have new levels of midfield depth from next season after another promising off-season window.
The Blues added wingman Jaxon Binns from the Dandenong Stingrays, who will join Hollands in competing for a wing spot against the likes of Lochie O'Brien and Matt Cottrell in 2023.
Onballer Matt Kennedy has rejoined the main program after overcoming post-season foot surgery, while Corey Durdin has also recovered from a shoulder reconstruction.