Martinez will start at third base and bat second in Sunday's game against the Giants.
Martinez had started each of the last three games while the Guardians faced left-handed pitching, going 3-for-8 with two doubles, six walks and three runs. The switch-hitting Martinez will stick in the lineup Sunday against a righty (Hayden Birdsong), though the 22-year-old's opportunities could still expected to be largely limited to left-handed pitching while he's up with the big club.