Duminy has been out of action since he suffered the freak injury in a warm-down session during the first Test against Australia in Brisbane last November.
"Proteas all-rounder JP Duminy continues to make satisfactory progress with the rehabilitation of his left Achilles tendon injury which is over five months post-surgery," a Cricket South Africa statement read. "Subject to further testing, he is on course to return to full activity by the end of May."
Team manager Dr Mohammed Moosajee revealed Duminy had returned to limited training in recent weeks.
"JP is five-and-half months post-op and has started sprinting at up to 80 per cent of maximum," he said.
"At present he is batting without restriction with the help of (coach) Gary Kirsten in the nets, and should be able to start bowling unrestricted within the next week.
"We are exercising extreme caution because of the sensitive nature of the injury but we remain cautiously optimistic of his speedy return to action."
South Africa are due to meet India in the Champions Trophy opener on June 6 in Cardiff.
Meanwhile, Faf du Plessis is closing in on a return to action.
The all-rounder has been in rehab for his lower back and is now in the sixth week of his rest period. He is currently with the Chennai Super Kings in the Indian Premier League and is scheduled to resume playing next week.
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