Kyle Bartley looks set to be out of action until November having undergone surgery on his knee.
The central defender was stretchered off after going up for a header and then landing awkwardly in the Swans’ Carabao Cup at MK Dons on August 22.
Though Bartley was initially ruled out for between six and eight weeks, the Swans were aware that the problem could prove to be more serious.
And the former Arsenal youngster has now had an operation which will mean a longer spell on the sidelines.
“We were disappointed to lose Kyle. He has now had surgery and we expect him to be out for around 12 weeks,” said Swans boss Paul Clement.
“The period of 12 weeks is an estimate, and we will have to see how Kyle responds to his rehabilitation.”
Bartley’s injury setback came at a disappointing moment given that he had just broken back into the Swans first team after a successful loan spell at Leeds.