The onset of the COVID-19 pandemic hampered Ritchie's final pre-major junior season with the Oakville Rangers, though toward the final months of what would have been the 2020–21 season restrictions were eased sufficiently for the team to practice and eventually play showcase games.
[8] Ritchie underwent shoulder surgery following the 2023 NHL scouting combine, and as a result made his 2023–24 season debut only on November 12.
[11] The Generals went on a deep run in the 2024 playoffs, reaching the OHL Finals, where they were swept by the London Knights in four games.
[9][12][13] After participating in his first Colorado Avalanche Rookie camp in preparation for the 2024–25 season, Ritchie was signed to a three-year, entry-level contract with the club on July 9, 2024.
[14] With a number of the team's veteran players sidelined by injury, he was named to the Avalanche's opening night roster.