Painter initially limped out of action during the first half of the Swans Area Final at MK Dons but returned to action on Saturday against Northampton. He lasted just 45 minutes before he was replaced and has now been dealt the blow that he faces another period on the sidelines.
The exact length of lay off is not yet known but the Swans will find out in the next day or so dependent on how an injection fares with the defender.
Roberto Martinez told the official site "He will have an injection in the next day or two,
"We'll have to wait to see how he reacts to it.
"If everything goes okay he'll be out for two to three weeks, but depending on the response it could be four or five.''
Roberto is yet to make a decision whether he will move into the loan market off the back of this news and the fact that Garry Monk still struggles with his injury.