[14] On November 11, he made his professional debut in a 123–94 loss to the Windy City Bulls, recording eight points, three rebounds, one assist, one steal and three blocks in 22 minutes off the bench.

[15] On September 30, 2017, Mockevičius signed a three-year deal with Lietuvos rytas Vilnius, but was not able to play from the start of the season due to injury.

[17] On July 25, 2018, Mockevičius signed a one-year contract with VL Pesaro of the Italian Lega Basket Serie A (LBA).

[22] On September 21, 2023, Mockevičius signed a short-term contract with BC Wolves of the Lithuanian Basketball League (LKL).

[23] On October 27, 2023, Mockevičius signed with VL Pesaro of the Lega Basket Serie A (LBA), returning for a second stint.