Gregson represented various youth clubs including Newcastle City Boy's (1969-74), Newbiggin Hall Boy's Club (1971-72) and Montagu & North Fenham Boy's Club (1972-74) being the club his father, Gordon, had played for 1949-50.
In 1971 Gregson was noticed by West Bromwich Albion scout, Bill Emery and was invited to take part in trials at the club during the Christmas holidays of that year.