Scotland have been left with the bare minimum number of front row players ahead of their encounter with South Africa this weekend.
Tighthead prop Geoff Cross has joined hooker Pat MacArthur on the injury list ahead of Saturday's game, while Euan Murray is also doubtful having been forced off against Samoa last weekend.
Scotland have not yet called upon a replacement for Cross, leaving them with just two fit hookers and four fit props throughout their squad.
"We came out with the big intention of broadening our base and will now have to broaden it sooner than we thought," said forwards coach Jonathan Humphreys.
"We are going to know a lot more about their fitness levels tomorrow. We had a recovery day today, then we will have assessments tomorrow morning and will pick the side according to who is left."
Scotland currently sit joint-bottom of the South African Quadrangular Series group, having lost their opening game 27-17 at the hands of Samoa.