The rookie first skated on October 5, 2005, getting no points in 3:58 of ice time in a 6–3 win over the Calgary Flames. Within the season's second week he would have his first assist, fight and goal. The assist came on a goal by Wes Walz on October 14, 2005 in a 5–3 loss to the Vancouver Canucks. Two days later, he had his first fight, knocking the Anaheim Ducks' Kip Brennan to the ice. He then scored his first NHL goal on October 19, 2005, beating San Jose Sharks goaltender Evgeni Nabokov in a 6–1 win over the San Jose Sharks. Boogaard finished his rookie season in the NHL with two goals, six points, while leading the Wild with 158 PIM in 65 games.
Boogaard's knockout of fellow enforcer Todd Fedoruk in a fight during a game against the Anaheim Ducks helped spark debate over increasing the punishment for fighting in the NHL. During this fight, Boogaard landed a brutal punch to the cheek sending Fedoruk to the ice. As a result, Fedoruk had to undergo surgery to reconstruct his shattered cheek using titanium plates. Fedoruk and Boogaard would later become teammates in Minnesota during the 2007–08 season. On November 6, 2005, Boogaard knocked out the Ducks' enforcer Trevor Gillies with an uppercut to the jaw.