Thomas was a member of Bob Johnson's final recruiting class and began playing at Wisconsin a year after the team won their third NCAA championship. The Badgers were still a powerful team in Thomas' first season, winning the WCHA Tournament and returning to the national championship game, only to conference rival North Dakota. Thomas had played well that season and was invited to participate at the 1982 World Junior Ice Hockey Championships. Team USA finished in 6th, a typical result for the team. The next season began shaping up even better for Thomas. Wisconsin looked ready to compete for a championship again while he spent time as both a forward and defenseman. Thomas played in his second WJC and, though he wasn't able to help them finish in the medals, Thomas led the US National team in scoring. His stellar play earned him an invite to the National Team for the upcoming World Championships and he remained with the national team for the remainder of the year. Thomas helped the US win pool-B with an undefeated record and a promotion to the top bracket for the subsequent world championship.