Celtic defender Greg Taylor will miss Scotland’s Nations League matches against Croatia and Portugal.
The left-back, 26, was absent for Sunday’s win at Ross County after picking up a calf injury in the midweek Champions League defeat to Borussia Dortmund.
Taylor, capped 14 times, also withdrew from the squad for the opening defeats to Poland and Portugal in this campaign.
Head coach Steve Clarke was already without 10 players through injury and there are doubts over Angus Gunn.
The Norwich City goalkeeper was withdrawn at half-time on Saturday after a taking a heavy knock to the ribs.
Vice-captain John McGinn is among those unavailable, with Nicky Devlin, Liam Lindsay and Andy Irving all called up for the first time.
Scotland visit Zagreb on Saturday before hosting Portugal three days later.
Portugal lead Group A1 on six points, with Croatia and Poland both on three and Scotland yet to get off the mark.
