Winnik was in training camp on a tryout basis. He was a free agent after a career-high 12 goals in 72 games last season for Washington.
The 32-year-old Winnik became more valuable to the Wild with a back injury limiting left wing Zach Parise, and Winnik was rewarded Wednesday with a contract. He's been on the fourth line with center Matt Cullen and right wing Tyler Ennis.
The Wild will be his eighth NHL team. He played two seasons for Wild coach Bruce Boudreau when they were both with Anaheim. Winnik has 76 goals and 152 assists in 717 games, plus 58 games in the playoffs.
The Wild open the season Thursday at Detroit.