Scotland duo Adam Ashe and Alex Dunbar are set to miss the first part of the Six Nations through injury.
The players have returned to their club, Glasgow Warriors, to continue their respective recoveries from problems which are expected to sideline them for "the coming weeks", an official Scotland statement confirmed.
Centre Dunbar picked up a thigh strain during the 22-5 win over Racing 92 in the Champions Cup on Saturday and left the field in the 50th minute.
Ashe, meanwhile, requires further treatment for a shoulder problem sustained in the 19-15 Premiership loss to Northampton Saints on January 17.
Scotland begin their Six Nations campaign at home to England on February 6.
On Monday, prop Alex Allan and back-rower Hamish Watson were added to the Scotland squad at a training camp at St Andrews.