In the following 2008–09 season, Hunwick was again initially reassigned to the AHL but after only two games was recalled and remained with the Bruins for the majority of the campaign. He scored his first career goal against Vesa Toskala in a 3–2 win over the Toronto Maple Leafs on November 17, 2008. His goal sparked a six-game scoring streak which tied Hall of Fame defenseman, Ray Bourque, as a club record for rookie defenseman. On January 10, 2009, in a game against the Carolina Hurricanes, Hunwick got into his first NHL fight, one-punching to knock down Justin Williams. Establishing a puck-moving role among the Bruins defense corps, Hunwick amassed a career-high 21 assists and 27 points in 53 regular season games. Hunwick made his post-season debut with the Bruins in game one of the Eastern Conference Quarterfinals against the Montreal Canadiens on April 16, 2009. However, on April 18, at a team meeting before game two against the Canadiens, Hunwick complained of abdominal pain. After consultation with the team doctor, it was determined that he needed medical treatment and Hunwick was taken to the hospital via ambulance. He underwent emergency surgery for a ruptured spleen, and was ruled out for the remainder of the playoffs.