With his ARU contract about to expire, speculation has mounted that Cooper will switch to rugby league or join a rugby union club in Europe.
Despite getting ready to box, he said his passion was still for rugby.
"Rugby's the game I love. I was brought up playing rugby union and rugby league. It's something I hold very close to my heart," he said.
"My desire for rugby will never fade. I very much love it, but it's out of my hands at the moment."
Williams has confirmed his return to rugby league, agreeing a one-year deal with the Sydney Roosters.
The All Black will fight Botha in a heavyweight bout in Brisbane on February 8. Cooper will fight in the cruiserweight division on the same card. His opponent has not been named. Supersport
