Ablett played his 350th game in round 5 of the 2020 season against his former club, Gold Coast, in what was also Joel Selwood's 300th game; he kicked a goal in the final quarter among 14 disposals. He later left the Cats' Perth hub after round 7 to be with his wife and son after earlier revealing that his son had been diagnosed with a rare degenerative disease. After finding out that he would not be allowed to return to play until the final home-and-away round due to Queensland travel restrictions, Ablett joined two players in the AFL's Gold Coast quarantine hub in September, before returning in Geelong's win against Sydney in round 18. He was among the best afield in Geelong's preliminary final win against the Brisbane Lions at the Gabba, kicking two third-quarter goals among 14 disposals. Ablett played his final game in Geelong's 31-point loss to in the 2020 AFL Grand Final the following week; he injured his left shoulder in the opening minutes of the game but continued to play, with scans later revealing that he had played out the rest of the match with a broken shoulder.