Scotland forward Zander Fagerson is a doubt for the start of the 2023 Six Nations because of a hamstring injury.
The 26-year-old tighthead prop sustained the damage during Glasgow Warriors' win at Zebre on 3 December.
Warriors say he is "expected to be out of action for the foreseeable, pending ongoing assessment".
Fagerson, who has 54 caps, is a key member of the Scotland team and was selected for the British and Irish Lions squad in 2021.
Scotland's Six Nations campaign kicks off with a Calcutta Cup match away to England on 4 February.
Edinburgh winger Darcy Graham could miss the game at Twickenham as he is not expected to return until February as a result of a knee injury. he picked up last week.
Glasgow lock Scott Cummings and flanker Rory Darge are both in a race to be fit for the tournament after missing the autumn Tests.