Cordner's decision comes a little over two months after his Sydney Roosters team mate Jake Friend, who was co-captain with him at the NRL club, cited head injuries as his reason for quitting the sport.
"My heart was telling me I wanted to play on, and I was doing everything I possibly could, but my mind and my head was telling me otherwise, it was dragging me the other way," Cordner said.
"For once in my life and my career I had to put my health and my happiness first. It was an extremely tough decision to make."