The Aussie agreed to a three-year deal with the A-League's only New Zealand club Wellington Phoenix, before his English club extended his contract by a year.
It seems Porter is keen to play in the Australian competition but the Professional Footballers' Associations in his homeland along with where he plays have to preside over the matter.
Phoenix chief executive Tony Pignata said, "At this stage Joel's case is still in progress."
"They've told him to stay even though he doesn't want to."
"He is keen to play in the A-League but unfortunately we have to overcome this hurdle."