[1] During the 2013–14 season, Sislo made his NHL debut with the New Jersey Devils, playing 8 minutes and 29 seconds and recording two shots on net, in a 5-3 loss to the visiting Chicago Blackhawks on January 3, 2014.

[2][3] After five seasons within the Devils organization, Sislo left as a free agent on July 1, 2016, signing a one-year, two-way contract to join the Colorado Avalanche.

[5] Sislo made an instant impact with the Marlies, regaining his scoring touch to finish the season with 8 goals and 16 points in 18 games.

At the conclusion of the season on June 14, 2018, Sislo was traded by the Coyotes to the Buffalo Sabres along with Brandon Hickey in exchange for Hudson Fasching.

[7] Sislo's rights were left to expire by the Sabres, and as a free agent he agreed to a one-year, two-way contract with the New York Islanders on July 2, 2018.