“I would love to return to the NBL and win a championship for Sydney to finish what we started this year,” Cooks said.
“Unfortunately, due to the changes in the league, my family and I feel like it’s best for me to opt out of my current contract and explore my options.
“My agent will continue to communicate with the Kings throughout the off-season in the hope that a new deal can be reached.”
Cooks made his move two days before the May 4 deadline for players to opt out of contracts so they could look at opportunities outside of Australia.
Cooks, who previously played in France with SG Strasbourg, was a key cog in the Kings’ run towards their first grand final appearance since 2008.
Kings coach Will Weaver said Cooks went above and beyond to recover from a knee injury suffered with the national team before last year’s World Cup.
“I’m grateful to Xavier for trusting us to play a role in his development as he strives to achieve his dreams of playing at the highest level,” Weaver said.