Career
Wallin was drafted in 1998 National Hockey League Entry Draft in the 6th round as the 160th overall pick overall by the Phoenix Coyotes. Before playing any games with the Coyotes, Wallin was traded to the Minnesota Wild for Joé Juneau on June 23, 2000. After winning the Swedish Championship with Färjestad in 2002, Wallin signed with the Wild during the summer of 2002.
Wallin spent three years in the Wild organisation, playing 19 games with the Wild and scoring ten points (six goals and four assists).
In September 2005, he returned to Sweden and Färjestad. After the season, he signed with Lugano of the Swiss Nationalliga A, but he stayed only one season with Lugano.
Wallin signed a one-year contract with the Toronto Maple Leafs on July 9, 2009. In returning to the National Hockey League Wallin played in a career high 60 games but was unable to contribute consistently offensively with 2 goals and 7 assists for just 9 points in the 2009-2010 season.
On May 25, 2010, Rickard returned again to Färjestad of the Studies in English Literature signing a four-year contract.