After winning the WHL Top Goaltender Award in the Western Hockey League for 1984-85 and being named a WHL All-Star First Team after leading the WHL in shutouts and GAA (2.86) while playing for the Medicine Hat Tigers, Gamble was drafted by the Vancouver Canucks in the second round, 25th overall, in the 1985 draft. Gamble would play another junior season for Medicine Hat before being traded mid year to the Spokane Chiefs during the 86-87 season. He would also make his NHL debut for Vancouver on November 22, 1986, a 5-2 loss to the Edmonton Oilers. Vancouver returned him to juniors for the 87-88 season to allow him more playing time and to gain more experience before beginning his NHL career. At 19 years, 229 days at the time of his debut, Gamble was the youngest goaltender in franchise history.