Stewart will be called up prior to Tuesday's matchup against the Rockies and either start or come out of the bullpen, J.P. Hoornstra of the Los Angeles Daily News reports.
Manager Dave Roberts has elected to call up Stewart ahead of Tuesday's matchup, and he'll give Kenta Maeda the nod for Wednesday's game. It's unclear whether Stewart will work in relief or get the start, but he figures to be utilized in some way. The 26-year-old has been near untouchable at Triple-A Oklahoma City this season, accruing a 2.08 ERA over 21.2 innings.