The former Wednesday striker was set to renew his aquaintance with the Owls and sign a full-time contract in the summer, before picking up a serious knee injury that looks to have ended his career.
It's a disappointing blow for the much-travelled striker, who has battled back from several serious injuries over the years and became a cult hero at Hartlepool last season.
And he is fondly remebered for his contribution at Hillsborough early in his career, providing competition for the likes of Hirst, Bright and Warhurst for a place in the first team.
Speaking in the Hartlepool Mail Turner said: "He has near enough retired.
"He is going to see how it goes over the next year but I don't foresee Gordon playing again."