The head of the NSW Fire Brigade Employees Union has emerged as the likely candidate to represent the Greens in the key Sydney seat of Grayndler.

The potential move of Labor's longtime Grayndler MP Anthony Albanese into neighbouring Barton has moved the inner-west electorate to the top of the Greens' target list at the next election.

Jim Casey, a former member of the International Socialist Organisation and state secretary of the FBEU has declared his candidacy for preselection in a YouTube video.

Speculation has swept Greens ranks that retired AFL star Adam Goodes had been approached to run for Grayndler but a party source poured cold water on the idea on Wednesday.