The change in the NHL's icing rule to reduce the risk of potentially damaging collisions partly stems from an incident that nearly ended Fedun's career.

After going undrafted, the quick-skating defenseman played four seasons at Princeton University. He had his best season as a senior with 22 points (10 goals, 12 assists) in 29 games in 2010-11. The Edmonton Oilers, his hometown team, signed him to a two-year contract March 8, 2011, and he was impressive during training camp before the 2011-12 season. But Fedun fractured his right leg during a preseason game when he was tripped by Eric Nystrom of the Minnesota Wild in a race for the puck to force icing. He missed all of 2011-12; the change to no-touch icing was made for the 2013-14 season.

By then, Fedun was in his second season with Oklahoma City, Edmonton's American Hockey League affiliate. He scored a goal in his first NHL game, Nov. 5, 2013, and scored his second goal two days later. He played four games in 2013-14 before being sent back to Oklahoma City.

Fedun spent the next four seasons bouncing between the NHL and the AHL. He played with the San Jose Sharks in 2014-15 and the Vancouver Canucks in 2015-16 before signing with the Buffalo Sabres on July 1, 2016. He had seven assists in 27 games with the Sabres in 2016-17, but spent most of 2017-18 going back and forth between the NHL and the AHL. He had one assist in seven games with the Sabres.

Buffalo traded Fedun to the Dallas Stars on Nov. 10, 2018. He scored in his Dallas debut 13 days later against the Ottawa Senators.