Steve Montador, the former NHL defenseman, was found dead at his Mississauga, Ontario, home Sunday. He was 35.

Steve Montador Dies

Montador was found dead at 2 a.m. Sunday morning, Peel Regional Police told USA Today. Attempts were made to resuscitate the athlete when emergency personnel arrived at the home, but they proved unsuccessful.

Montador’s cause of death remains unknown. An autopsy will be conducted, though no foul play is suspected.

“We are not treating it as anything criminal,” police spokeswoman Fiona Thivierge said. “It’s a sudden death, so there’s nothing to indicate anything untoward, just natural causes as far as we know.”

Over the course of his 10-season career in the NHL, Montador played on six teams, the last of which was the Chicago Blackhawks.

“With deep sadness we mourn the unfortunate loss of former Blackhawk Steve Montador,” the Blackhawks said in a statement. “We join the many others throughout the NHL in keeping Steve’s family and friends in our thoughts and prayers during this difficult time.”

NHL commissioner Gary Bettman also released a statement upon learning of Montador’s untimely death. “The NHL family was saddened to learn of the passing of Steve Montador,” Bettman said. “Steve’s career was defined by a passion for the game and a determination that made him a great teammate as well as a respected opponent. We extend our deepest sympathies to Steve’s family and friends.”

In addition to the Blackhawks, Montador had played for the Calgary Flames, Florida Panthers, Buffalo Sabres, Anaheim Ducks and Boston Bruins. After suffering a season-ending concussion during the 2011-12 season while playing with the Blackhawks, Montador spent the 2012-13 season with the Blackhawks’ affiliate in Rockford, Ill. For the 2013-14 season, he played in Russia’s Kontinental Hockey League before once again suffering a severe, sidelining concussion.