The Mariners placed Miller on the 15-day injured list Wednesday due to a left oblique strain.
Miller strained his left oblique in late February and was limited to just one appearance during Cactus League play. He's thrown a pair of bullpen sessions recently and hasn't encountered any known setbacks, but the righty will require several weeks to be build back up, per Adam Jude of The Seattle Times. Emerson Hancock will occupy a spot in the Mariners rotation until Miller is ready to make his 2026 debut.