Pelehos was ranked as the 15th best player in the Canadian Football League's Amateur Scouting Bureau final rankings for players eligible in the 2022 CFL Draft.[2] He was then drafted with the second overall pick, and first by players in U Sports, by the Ottawa Redblacks.[3] He began the 2022 season on the injured list, but made his professional debut in week 2 on June 17, 2022, against the Winnipeg Blue Bombers, as a backup offensive lineman.[4] He spent eight games on the injured list and played in ten games for the Redblacks during his rookie season.[4][5]
Following training camp in 2023, Pelehos won a starting job and earned his first career start at right tackle on June 10, 2023, against the Montreal Alouettes.[6] He had eventually lost his starting role to Dontae Bull in August, but reclaimed the starting position on October 14, 2023.[7][8] He played in 14 regular season games in 2023.[9]