Mathews scored 44 and 34 points in the tournament's quarterfinals and semifinals, respectively, to help the Bisons reach the championship game, in which they were defeated by Texas.

Under the terms of the deal he divided his time between the Wizards and the NBA G League affiliate, the Capital City Go-Go.

[6] On October 23, 2019, Mathews made his NBA debut, coming off the bench in a 100–108 loss to the Dallas Mavericks with an assist.

[10] On October 18, he was claimed off waivers by the Houston Rockets, who later turned his deal into a two-way contract with the Rio Grande Valley Vipers.

[12] On February 9, 2023, Mathews and Bruno Fernando were traded to the Atlanta Hawks in exchange for Justin Holiday, Frank Kaminsky and two future second-round draft picks.