After leaving school, Preston continued playing rugby union with Preston Grasshoppers before later joining Fylde RFC. He was the country's leading try scorer during the 1987–88 season, and received a call up for the England B team,[5] scoring a try in a 35–9 win against Italy B at Welford Road, Leicester on 4 March 1988.[6] A few days later he switched codes to rugby league, signing a contract with Wigan.[7]
Preston made his debut for Wigan on 1 April 1988 in a 10–9 win against local rivals St Helens,[8] and scored his first try for the club a few days later in a 42–16 victory against Swinton.[9] Later that month, he scored five tries in a 62–10 win against Hunslet.[10]
Preston's best season for Wigan came in the 1989–90 season. He was the club's top try scorer with 32 tries in 41 appearances,[11] helping the club win the league championship that season. He also played for Wigan in the 1989–90 Regal Trophy final victory against Halifax, and scored two tries in the club's 36–14 win against Warrington in the 1990 Challenge Cup final.
In June 1991, he was transferred to Halifax for a fee of £50,000.[12]