Swansea centre back Kyle Bartley is out for up to eight weeks after damaging a knee ligament in Tuesday's 4-1 League Cup win over MK Dons.
The 26-year-old, who played in all three of Swansea's games so far this season, landed awkwardly after a challenge in the 80th minute and was taken off on a stretcher.
Swansea said on their website that the Englishman had damaged his medial ligament and would see a specialist next week.
Following their victory over MK Dons on Tuesday, Swansea have been drawn away to Reading in the third round of the Carabao Cup.