The Wild start the season Saturday against Colorado.
Dumba was the team's first-round draft pick this year, the 12th overall selection, and will be one of seven defencemen on the initial roster. Marco Scandella remains in the AHL while he's recovering from a groin injury.
Left wing Matt Kassian, a 6-foot-5, 247-pound enforcer, also has a spot. Coach Mike Yeo said he's important for protection of the team's stars.