The Wild announced the move Thursday. Prosser became a free agent last summer and signed with St. Louis, only to be waived by the Blues this week.
Prosser scored two goals and had six assists and 58 penalty minutes in 53 games with the Wild last season. The 28-year-old from Elk River, Minnesota, has totaled 21 points - three goals and 18 assists - and 127 penalty minutes in 126 games during parts of five seasons with the Wild.
The 6-foot-2, 203-pound defenseman first signed as a free agent with Minnesota in 2010.