Holdsworth, 29, had asked to leave the club due to personal and family reasons, despite having one-year left on his contract.
“It hasn’t quite worked out for him at Hull FC and a return to an Australian club is probably an environment better suited to him personally.
“Our focus remains on 2014 and building a competitive squad with players that are fully committed to the club, their teammates and the fans.”
“We have been aware that Daniel could be leaving the club this autumn and have planned accordingly.”
Holdsworth came to Super League in 2010, and impressed during three years at Salford, earning him a switch to Hull.
However, he suffered an injury hit stay at the KC Stadium, and never really recovered from a concussion knock early in the year.