John started the 1990 AFL season in the Under 19s competition but due to an extensive injury list, made his senior debut in Round 10, against Essendon Football Club.
With the Swans unable to field any supporting ruckmen on his return, many opposition teams adopted the tactic of rotating two players against John in an attempt to shut him down.
Playing against Essendon at the Sydney Cricket Ground, John had his larynx crushed in a ruck duel with Simon Madden and almost died.
After the game it was revealed all players on the Swans interchange bench had also sustained injuries earlier in the match and had been ruled out of play by the club physician.
He was then picked up by North Melbourne with selection 63 in the 1993 AFL draft and suffered a dislocated shoulder early in the season which ultimately resulted in his retirement from the game at only 22yrs of age.