Georgian international lock Konstantine Mikautadze faces at least two months on the sidelines with a fractured vertebra, his club Montpellier said on Monday.
The 26-year-old was injured during a unique scrummaging training session with his country against England last week.
He underwent tests on Monday where the damage was discovered.
Having engaged in a similar forwards training session with Wales ahead of last year's November internationals, England repeated the exercise on Tuesday and Wednesday last week with Georgia to help prepare for this weekend's clash with Scotland at Murrayfield.
Top 14 leaders Montpellier are already without South African lock Jacques Du Plessis, who underwent an operation in December on a torn Achilles tendon.
It leaves New Zealander coach Vern Cotter with only three senior second rows: South African pair Paul Willemse and Nico Janse Van Rensburg, and veteran former All Black injury cover Jarrad Hoeata.
© 2018 AFP