Nigel Atangana will undergo surgery on Thursday on the ruptured Achilles tendon injury he suffered in last week's defeat to Crawley Town.
The French midfielder went down in the second half at The People's Pension Stadium and was stretchered off, with scans later revealing the full extent of the injury.
He is now facing between six and nine months out following Thursday's surgery.
The 29-year-old will be operated on by the same surgeon who treated Atangana's teammate Jordon Forster when the Scotsman suffered the same injury in August 2017.
Atangana had made 34 appearances in all competitions for the Robins this season, scoring twice in December in the 2-2 draw at Port Vale and 3-1 Boxing Day win over MK Dons.