Having had time to rest the problem over the past few days, 23-year-old Radwanska has insisted that the pain is subsiding.
"It's sometimes worse but it feels better right now," Radwanska told reporters. "That's about it.
"It's always different when I'm playing matches or I'm just practising and not pushing that much. Of course I had some rest before the US Open. I'm really taking care of it right now. It's really better."
Radwanska has never ventured beyond the last 16 in New York.