It’s understood the Reds would not stand in the way of the 32-year-old attacking midfielder were another A-League door to open, or an opportunity emerge in south-east Asia or the Indian Super League.
Brisbane Roar have recently been linked with bringing 37-cap Troisi to Queensland.
However a club spokesman last week denied such a move was on the cards.
Troisi has scored once in 17 appearances across all competitions since joining his hometown team from Melbourne Victory a year ago.
He is due to collect the lion’s share of his tiered contract payments in 2020-21.
But with cost-cutting widespread across the competition ahead of a salary cap drop to $2.1 million, the Reds could save up to $350,000 by allowing the much-travelled schemer to depart for what would be the 11th club of his 13-year professional career.
His arrival in South Australia was hailed by the club as a minor coup but Troisi didn’t make the impact he would have hoped for in a team that fell short of a finals spot.
Coach Carl Veart has already lost several key players with the likes of Riley McGree, Lachlan Brook, Paul Izzo, Kristian Opseth, George Blackwood and Nikola Mileusnic heading offshore.
Troisi has played in England, Turkey, Italy, Belgium, China and Saudi Arabia.
Adelaide United were contacted for comment.