Kozma signed a minor-league contract with the Athletics on Wednesday, Matt Kawahara of the San Francisco Chronicle reports.
Kozma appears set to serve as organizational depth for Oakland in 2021 after spending the 2020 season with Atlanta's alternate squad. The 32-year-old hasn't appeared in the majors since 2018, and he slashed .263/.340/.414 with seven home runs and 51 RBI with Triple-A Toledo in 2019.