Mack underwent an MRI on Monday, the results of which confirmed a torn Achilles, Tom Pelissero of NFL Network reports.
The severity of Mack's injury will no doubt cause him to miss the remainder of the 2020 season, leaving Jonathan Taylor and Nyheim Hines in line to handle increased workloads out of the Indianapolis backfield. Mack, who compiled 1,091 rushing yards across 14 games in 2019, will lose the rest of his contract year. He's set to become an unrestricted free agent in 2021.