Scotland prop Zander Fagerson will miss the bulk of the Six Nations after suffering a foot injury.
Glasgow revealed the 21-year-old would be out for up to eight weeks after an accident in training.
Scotland face Wales, France and England in February and Fagerson could also struggle to be fully fit in time to face Ireland on March 10.
Fagerson already has 15 caps and was ever-present for his country throughout 2017.
Warriors suffered a triple blow with Callum Gibbins and Scott Cummings also facing lengthy spells on the sidelines.
Gibbins has undergone surgery after an Achilles problem halted the flanker's impressive start to his Scotstoun career. Glasgow say the New Zealander faces up to 12 weeks out.
Second-row forward Cummings will be out for about eight weeks after suffering a hand injury in training this week.
There was better news for Glasgow and Scotland after Adam Ashe was included among the replacements for Warriors' Guinness PRO14 clash with Zebre in Italy after 10 weeks on the sidelines following ankle surgery.
Zebre have beaten Connacht and Ulster along with Southern Kings this season and head coach Dave Rennie had a warning for his players after they got back on track with a 17-0 win over Edinburgh following defeat at Murrayfield.