The deal was done on Tuesday.
Fontaine had 13 goals, eight assists and a plus-6 rating for the Wild in 66 games last season as a rookie, ranking fourth on the team in goals. Playing primarily on the third line, Fontaine also had one goal and one assist in nine playoff games.
The 26-year-old Fontaine's goal total last season was the third-highest by a rookie in Wild history, and his plus-minus rating was second. The former Minnesota Duluth star also recorded the franchise's first hat trick by a first-year player, when he had three goals in a game at Phoenix in January.