The Northern Irish ‘keeper took ill after a spell away on international duty in November, and was taken to University Hospital Wishaw where he was treated.
The Fir Park side confirmed the 30-year-old would require “ongoing treatment” during his recovery and is unable to play for six months, meaning a comeback in summer 2019 looks the most likely scenario.
Carson, who has had spells with Sunderland, Chesterfield, Lincoln, Bury, Portsmouth, Cheltenham and Hartlepool, joined the Steelmen in June 2017, and has appeared four times for Northern Ireland.
He has 63 appearances under his belt for Stephen Robinson’s side.
On Twitter last week, the goalkeeper wrote: “It’s a long road ahead but I feel positive and I know how much worse things could have been.”