His hometown club, Melbourne Victory, are rumoured to be lining up a move for the 26-year-old in time for the new A-League season starting in August, according to reports in the Australian press.
Allsopp previously played for Victorian Institute, South Melbourne, Carlton Soccer Club and Port Melbourne Sharks before moving to England in 1998, signing for Manchester City.
He went on to play for Notts County before Peter Taylor signed him for just under £100,000 last year.
15 goals in his first season at the KC Stadium helped City to promotion, but he has struggled to hold down a first team place this year, starting 13 times and coming off the bench a further 15 times, scoring 5 goals.
Should City win promotion again he may find himself surplus to requirements in the Championship.