On November 7, 2020, Mack signed a two-month deal with European powerhouse Panathinaikos of the Greek Basket League and the EuroLeague.Panathinaikos officially announces signing of Shelvin Mack His contract was subsequently renewed for the rest of the 2020-2021 season. On June 6, 2021, Mack parted ways with the Greek club amidst the domestic competition finals against Lavrio in order to attend to personal matters overseas. In 23 GBL and 21 EuroLeague games with the Greens, Mack averaged 6.5 points, 2 rebounds, and 4 assists.
