Haggerty has made the Mariners' Opening Day roster, Daniel Kramer of MLB.com reports.
The versatile 26-year-old flashed potential in his first Mariners season in 2020 with a .260/.315/.400 slash over 13 games. Despite the fact that he followed it up with just a .239 average this spring, his experience playing every position in the field except catcher and first base made him too valuable not to stick.