Protas started his career in his hometown of Vitebsk. He spent two seasons with the Belarus U17 team that played in the Vysshaya Liga, the second league in Belarus, before being selected 26th overall by the Prince Albert Raiders in the 2018 CHL Import Draft. He joined the Raiders for the 2018–19 season, and finished with 40 points in 61 games. Heading into the 2019 NHL Entry Draft Protas was the 30th ranked North American skater, and was selected 91st overall by the Washington Capitals. He played for Prince Albert in 2019–20 season, which was ended prematurley due to COVID-19; in 58 games he had 80 points, which placed him ninth in the WHL in scoring and the highest European player.