[1] As a free agent, Gross attracted NHL interest, opting to sign a two-year, entry-level contract with the Arizona Coyotes on April 12, 2018.

[2] He immediately joined the Coyotes' AHL affiliate, the Tucson Roadrunners, on an amateur try-out, making his professional debut in a solitary appearance and registering 2 assists to end the regular season, in a 6-3 victory over the San Diego Gulls on April 14, 2018.

On April 2, 2021, Gross registered a career-high 3 assists against the Anaheim Ducks, the most tallied by a Coyotes rookie defenseman in a single game since Keith Ballard in 2006.

As a free agent from the Coyotes, due to lack of games played at the NHL level, Gross was signed to a one-year, two-way contract with the Colorado Avalanche for the 2021–22 season on July 31, 2021.

[11] As a free agent from the Avalanche, Gross capitalised on his successful season by agreeing to a two-year, $1.525 million contract with the Nashville Predators on July 13, 2022.