Tragic: Steve Montador, 35, who played for six franchises throughout his 14-year career, was found unconscious in his Mississauga, Ontario, home on Sunday

A former NHL defenseman who had a history of depression and was plagued by concussions throughout his career has died.

Steve Montador, 35, who played for six franchises throughout his 14-year career, was found unconscious in his Mississauga, Ontario, home on Sunday.

A cause of death has not been released, but according to the Star Tribune, foul play is not suspected.

He began his NHL career with the Calgary Flames during the 2001-02 season.

He last played in the league 2011-2012 when he suffered a season-ending conclusion during a game.

The defenseman went on to play for the Florida Panthers, Anaheim Ducks, Boston Bruins, Buffalo abres and Chicago Blackhawks

He finished his playing career in the KHL in Russia

Montador had 33 goals and 98 assists in 571 career NHL games.

After hearing news of his passing, former players and organisations took to Twitter to pay tribute.

Former Sabres teammate Luke Adam wrote: 'So sad to hear the passing of my former teammate Steve Montador. 'I will always remember how good you were to me as a rookie Monty.'

Vancouver Canucks goaltender Ryan Miller wrote: 'Monty laughed a lot and made the rink a fun place. So sad. Just spent some time with him this summer.'

The Chicago Blackhawks organization issued the following statement on Montador's passing. They said: 'With deep sadness we mourn the unfortunate loss of former Blackhawk Steve Montador. We join the many others throughout the NHL in keeping Steve's family and friends in our thoughts and prayers during this difficult time.'

Investigation: A cause of death has not been released, but foul play is not suspected

The Calgary Flames also wrote: 'It is with great sadness to learn of the death of former defenseman Steve Montador. Condolences to Steve's family.'

The Buffalo Sabres added: '[We] were deeply saddened to hear about the passing of Steve Montador.

'Steve was a passionate hockey player, a valued member of the Sabres family and a highly respected individual off the ice. Our thoughts and condolences are with Steve's family and friends during this difficult time.'

In March 2013, during his recovery, he opened up about his issues with depression and anxiety.

He said: I know people talk about sports being a microcosm for life, and it's very true that way.' he said. I can see why people have a hard time with … being taken away from something they love to do.'

'There's a lot of uncertainty, a lot of fear, a lot of anxiety and depression. I've had a lot of help to work through that, and I feel like I've taken the right steps.'