Scotland have called up Bristol City full-back Richard Foster as a replacement for Charlie Mulgrew.
Defender Mulgrew has succumbed to the Achilles injury that kept him out of Celtic's draw against Hibernian on Saturday and will miss the opening World Cup qualifier against Serbia.
Former Aberdeen captain and Rangers player Foster, 27, is uncapped, while the versatile Mulgrew joins a number of full-backs unavailable to manager Craig Levein.
Steven Whittaker and Phil Bardsley were missing from the original squad because of ankle injuries and Danny Fox and Russell Martin pulled out.
Levein called up Huddersfield left-back Paul Dixon and MK Dons defender Gary MacKenzie on Monday.
Wolves centre-back Christophe Berra was on Thursday due to join up with the squad after his partner gave birth.