Alex sustained a thigh strain in Glasgow's 22-5 win over Racing 92 on Saturday and will be sidelined for the coming weeks.
Further assessment on the shoulder injury sustained by Adam Ashe in his club’s Champions Cup match loss to Northampton Saints a fortnight ago also confirmed the back-row will be unavailable for selection for the coming weeks.
The pair will continue their recovery and ongoing assessment under the care of the Glasgow Warriors medical team.