He started 13 games in 2019, catching 63 passes for 987 yards and 10 touchdowns, earning second team all-Mountain West Conference honors.

[4] Mariner signed with the Ottawa Redblacks of the Canadian Football League (CFL) on January 21, 2022.

[5][6] Mariner began the 2023 season on injured reserve but was upgraded to the active roster after the Redblacks cut Quan Bray on June 29, 2023.

[7] He moved between the active roster and single game injury list (healthy scratch) several times during the 2023 season.

[9] On April 4, 2024, Mariner signed with the Michigan Panthers of the United Football League (UFL).