Brubaker was optioned to Triple-A Indianapolis on Saturday.
Brubaker was one of eight cuts announced by the Pirates as the team trimmed its major-league camp roster down to 54. He'll likely be included in the Indianapolis rotation for the second straight season after turning in a 3.10 ERA, 1.32 WHIP and 96:36 K:BB in 119 innings (22 starts) for the affiliate in 2018.