Hishon with a concussion; Hishon missed the rest of the Memorial Cup and the entire 2011–12 hockey season with post-concussion syndrome. In part due to this hit, Hockey Canada redefined the rules to make clearer a zero-tolerance policy for head hits. Professional Colorado Avalanche Hishon's recovery extended into the following 2012–13 season, before he was belatedly cleared for non-contact practice with the Avalanche's AHL affiliate, the Lake Erie Monsters, to begin the new year. Hishon was finally scheduled to make his long-awaited professional debut with the Monsters against the Toronto Marlies on March 19, 2013. It marked a return from his concussion just two months shy of two years. In his fifth game, Hishon scored his first professional goal in a multi-point effort against the Chicago Wolves on March 29, 2013. However, on April 12, in his ninth game and on his first shift against the Hamilton Bulldogs, Hishon's season was ended after he suffered a second concussion received in a hit from behind by Joey Tenute. With an early prognosis of a less severe concussion than previously endured, it was anticipated Hishon would recover in time to prepare for the following season. Hishon played for the majority of the 2013–14 season scoring 10 goals and 24 points despite missing 26 games due to injury. He was an emergency call-up during the first round of the 2014 Stanley Cup Playoffs, debuting in Game Four against the Minnesota Wild. At the end of the season, the Avalanche gave him a qualifying offer of $900,000, and he was reportedly signed to a one-year two-way contract paying $850,000 in the NHL. In the 2014–15 season, Hishon again played primarily for the Lake Erie Monsters in the AHL, playing 53 games and scoring 16 goals and 36 points. In March 2015, Hishon was called up to the Colorado Avalanche. He scored his first NHL goal on April 7, 2015 against goaltender Pekka Rinne of the Nashville Predators. In the summer of 2015, Hishon signed a one-year two-way contract paying $890,000 in the NHL. In the 2015–16 campaign, he made 62 appearances for Colorado's AHL affiliate, the San Antonio Rampage, unable to earn a recall to the NHL for the duration of the season. Europe On May 2, 2016, as an impending restricted free agent with the Avalanche, Hishon opted to embark on a European career, signing two-year deal with Finnish club, Jokerit, who compete