The Wild announced the signing Sunday.
A 21-year-old native of Fribourg, Switzerland, Bertschy had 14 goals, 16 assists and 26 penalty minutes in 44 games with SC Bern in the Swiss League in 2014-15. He added a goal and two assists in seven playoff games.
He had three goals and two assists for Switzerland in six games at the 2013 World Junior Championship.
The 5-foot-10, 189-pounder was selected by Minnesota in the sixth round of the 2012 draft.