The 34-year-old suffered the blow in South Africa's 1-0 friendly loss to Brazil in Sao Paulo on September 7, and has been ruled out of action for six weeks.
However, Bafana Bafana's record scorer, with 31 goals, is determined to make a swift comeback.
"I still feel a bit of pain but it's getting better by the day," McCarthy told Pirates' official website.
"Sitting out for six weeks is a long time, especially for a guy like me, who enjoys being on the field. Fortunately I've already started rehabilitation which will obviously speed up my recovery process.
"I hope to recover a lot sooner than what the doctors say but only time will tell," concluded the former FC Porto man.