The 32-year-old became something of a cult hero with the club in the 2019-20 season, which ended prematurely, but with a Challenge Cup in the cabinet.
And Fox led the tributes and spoke of his presence in the Steelers locker room as well as on the ice.
🍊The Steelers are devastated to learn of the passing of Marek Troncinsky. The club wish to pass on its condolences to Trons family & friends around the world.
“Marek was such a pleasure to have with us last year,” he told the Sheffield Steelers website. “He had a light hearted character and seemed to always be smiling and joking around with the guys.
“From the hockey side he could do it all. A big heavy D who skated so well and could play in all situations.
“I was absolutely devastated to hear the news last night and my thoughts, prayers, and condolences go out to his family, and all his friends.
“This is a very sad day and the hockey world has lost a really good one, RIP Tron”.
Troncinsky joined the club in October 2019 after spent his entire career in his native country, starting that season with HC Litvinov before moving to England.
In 52 games for Steelers in all competitions, he scored 12 times and made 34 assists and spent last season in Romania with Gyergyoi and had agreed to return to the UK for the new season.
Troncinsky leaves behind a wife and young daughter.